If you are having trouble understanding what is outrageous and even terrifying about those passages above, try reading them again, replacing the words "Islamist", "Muslim" and "Islam" with "Zionist", "Jew/Jewish" and "Judaism" respectively. And recall that in the years leading up to the Holocaust, Jews were blamed for the "Bolshevism" that apparently threatened prosperous Western Christian civilization, and some of the first Jewish victims of the Holocaust were rounded up during sweeps for communists and other leftists. Today, Muslims are blamed for the "Islamist extremism" that we are told threatens prosperous Western Civilization, whether that means prosperous Judeo-Christian civilization or prosperous Secular Scientific Civilization. Bolshevism did not turn out to be such a great prize, and Islamist extremism is likewise uninviting, but the Holocaust is a vivid reminder that a legitimate concern about an emergent threat is no excuse for stirring up potentially mass murderous scapegoating against some other ethnic group's religion. Nor, for that matter, can such concerns justify the expedient evisceration of one's "scruples"--which are often precisely the scruples that contributed to making one's own civilization compelling.
At this point it is fair to object that I have quoted both Harris and Hitchens selectively, painting a considerably greater contrast between them than in fact exists. I have been especially selective with Hitchens, making him out to be a sentimental, weepy, Martin Luther King-loving, museum-going liberal milksop. Some fans of Hitchens may thank me for that. By implying that the passages I selectively quoted are the core of his ethos, I have been very charitable to that ethos. However, Hitchensian fundamentalists (or anyone who supports honest textual reading really) would say I have cherry-picked the parts of Hitchens that best resemble my own weepy liberal milksoppery and have failed to face the more challenging and discomfiting theses in his polemic.
I have indeed neglected up to now the statements Hitchens makes that might be interpreted as exalting atheism to be the only reliable ideological framework for arriving at true propositions about the universe. Likewise, I have offered no illustration of his caustic condemnation of all competing worldview alternatives as gross, stupid and evil descents into atavaism, detestable epistemological and moral errors hobbling a "mammalian" species that only by atheism has some hope of living up to its uniquely human DNA. I have treated Hitchens' support for the Iraq War and Islamophobia as ideological tics he picked up from running with a bad crowd, and avoided reprinting the most embarrassing quotations born of these attitudes. I even used Sam Harris as a kind of "at least he's not as bad as this guy" foil, though Harris in fact has been a much less enthusiastic and consistent defender of the Iraq War. I have also implied that Hitchens in no way seeks to logically ground his pro-war Islamophobia in his atheism--though he quite explicitly does this, and indeed that is arguably the point of the title for God is not Great and of most of the book itself.
I could say it was out of respect for ordinary atheists that I exercised this self-censorship (though this would be a dodge). And it is at least true that I do not want to argue against what I consider to be a straw man version of atheism--I am wary of imitating those who treat Pat Robertson's sermons and media rantings as the most intellectually and morally advanced statements on Christianity or Osama bin Laden as the most astute interpreter of Islam. Even if Hitchens' half genteel half rabid vision sometimes converges with Harris's more consistently apocalyptic and ruthless one, a solid majority of atheists presumably do not hold political visions that mesh much with either of these New Atheist views.
The most benign quotations from Hitchens (about admiring Martin Luther King, enjoying art and conversation and the good things in life, etc), even if they do not fully represent Hitchens' current center of gravity, at least form a reliable and charitable impression of atheists as people. I would not call these quotations a Nicene creed for atheists, exactly, but rather a good guess at what most atheists would probably nod assent to most of the time. I suspect, in fact, that my selective reading is quite close to what most atheists would say are the ethical-aesthetic correlates of atheism. In contrast, the moral compromises with destructive power that Hitchens or Harris can sometimes make are not at all close to this essence. I imagine that with some prodding even Hitchens would eventually admit that his contrarian defense of the Iraq War and his anti-Islam chauvinism are his own guilty mammalian pleasures rather than necessary features of atheism. And why should I judge Hitchens or any other atheists by the worst that I can find about them and not rather by the best? Would I want myself or my own faith to be judged that way?
Perhaps with my charitable selectiveness, I have done to God is Not Great what religious liberal-leftists do to the Bible--pick out the humane and numinous parts of it, and throw away the violence-worshipping, slavery-justifying genocidal parts that pop up from time to time. If any atheists take God is Not Great as the authoritative and unalterable Word of Atheism, they might say that I have in fact demeaned the distinctiveness of Hitchensian atheism by embracing only the parts of it that fit with my bleeding heart worldview. Thus, if I were ever to explicitly claim atheism one day, I would have to admit to being little more than a "cafeteria" atheist--picking and choosing the parts of atheism that I like, and otherwise ignoring or condemning Hitchens' papal encyclicals to join the forces of Shock and Awe as well as Harris's fatwahs to rain down fires of death and destruction on Islamic Civilization. Those who would worship the Words of New Atheism might condemn any atheist who followed my seductive lead as an apostate, unfit to be called an atheist.
Of course most atheists would note, correctly, that in fact they generally do not feel the need to worship every word written by those they generally admire, nor do they feel the need to execute or shun their "apostates", or to go around persecuting each other for having heretical alternative interpretations of atheism. These are, for the most part, religious pathologies--and perhaps also pathologies of those who embrace certain ideologies with religious intensity, e.g. communism. And yet this type of factionalism, while not yet leading to bloodletting among the 21st Century faithless, is not something that atheists are immune to by any means.
Not-so-new atheists favor strategic alliances with religious liberals on matters of teaching evolution in schools, supporting rights that religious people tend to oppose (like LGBT rights), condemning violent fundamentalism and opposing anti-atheist discrimination and prejudice. Those who fully embrace the New Atheist agenda, on the other hand, are called to battle valiantly against all religionists--fascist, conservative, moderate, liberal and liberationist. Though all sides of the non-believing divides can be sharp-tongued with each other, the New Atheist position is arguably the one that is most fiercely opposed to nuance. Richard Dawkins has even seen fit to write an essay called "I'm an atheist, but..." condemning those who are not sufficiently hostile to religion or emphatic in their atheism.
Though Hitchens fights off this New Atheist lack of nuance in some ways, he lets it creep into his judgment in many other ways, and even lets it color his account of Martin Luther King (which, as noted earlier, was otherwise quite compelling). Hitchens bothers to mention King at all in a book exalting atheism because King's life and work is such a clear anecdotal counterexample to the thesis that "religion poisons everything." While giving King his due for the most part, Hitchens copes with King's status as a religious-yet-nevertheless-kind-and-courageous-person by asking us to entertain the possibility that perhaps King was not so religious after all.
Such an argument does not have to be preposterous. For instance, insofar as King's reading of the Bible was more charitable than it was literal (focusing on the libratory and numinous aspects of the text), in the eyes of some Christians he would not meet the criteria for being a true Christian. To the most politically and economically muscular authorities of Christianity, the faith requires undoubting belief in every proposition in the Bible as the literal Word of God (though of course non-literalist Christians would retort that politically muscular churches do not own interpretive rights to Christianity, and that even so-called Biblical literalists tend to be transparently guilty of selective textual emphasis  ).
Hitchens' argument for King's un-Christianness takes this Christian literalist argument and turns it inside out. His case rests on the assertion that King was too humane and reasonable to be counted among the Christians: "At no point did Dr. King"even hint that those who injured and reviled him were to be threatened with any revenge or punishment, in this world or the next". In no real, as opposed to nominal sense, then, was he a Christian" (God Is Not Great, p. 176). Though Hitchens does not make the outright claim that King was just offering the rhetoric that he knew other Christians would be receptive to in order to advance atheist-style social justice in a Christian-controlled country, he makes this inference very easy to draw: "The entire self-definition of "the South' was that it was white and Christian. This is exactly what gave Dr. King his moral leverage, because he could outpreach the rednecks. But the heavy burden would never have been laid upon him if religiosity had not been so deeply entrenched to begin with" (p. 179).
I myself very much doubt that King's public religiosity weighed upon him as a "heavy burden," or that he was telling politically savvy white lies when he claimed theism or Christianity. Unlike Hitchens' neoconservative friends who (at least used to) follow Leo Strauss's injunction to publicly embrace right wing fundamentalist religion as a "noble myth" while secretly scoffing at it, I do not think that King craftily showed a religious face to the people while privately rejecting Christianity as plebian nonsense appropriate only for the spinal cord-driven masses. A smart heroin dealer does not shoot up himself, but it is safe to say from King's speeches and from the testimonies of others close to him that he had a God-loving needle in his arm--and the movement he came to lead was better off for it.
Hitchens is not the first to surmise that King was just using religion to get America behind his deeply secular socialist-humanist agenda, but unlike most others, Hitchens makes this smear on King's political and religious honesty with charitable intentions. FBI director at the time J. Edgar Hoover infamously reasoned along similar lines, but instead of being touched by the ethical excellence of what King was trying to do, Hoover felt his power and ideology threatened by it. Hoover believed King was a communist, not a Christian (he considered them mutually exclusive), because King was way too cozy with progressive forces like labor leaders, anti-war activists and fans of Swedish social democracy (and Sweden is, truth be told, one of the most atheistic societies in the world, and a fine example of what a healthy model of good living a largely atheist society can provide).
Although Hoover's wire tapping, blackmail, encouragements to commit suicide and general intimidation did not impede King's work as much as Hoover had hoped, the fact that Hitchens still echoes Hoover's libel and has probably convinced many of his readers to believe it too suggests that Hoover made some long term contribution to distorting our memories of the man.
Still, since Hitchens' attempt to out King as a faux Christian is meant to be complimentary, it is an interesting twist on Hoover's hysterical paranoia. In the early years of Christianity, when Christians embraced non-violent radicalism against Roman imperial tyranny and Christian devotees cheerfully went to be eaten by circus lions after short lives of relentlessly teaching peace and brotherhood, they began to gain a good reputation among the more enlightened Roman citizenry. The numinously-inclined worshippers of Roman gods were potentially moved by comparisons of Christian martyrdom to that of the pagan hero Socrates. To the extent Christians could portray themselves as "just like the best pagans" they gained pagan sympathy.
It is common to compliment individuals of another group that you generally detest by saying that some of them are in fact honorary members of your own group. The classic Christian parable of the Good Samaritan, in fact, is about how a Samaritan, in spite of his obvious ethno-religious shortcomings, could live up to and even exceed the expectations of Jewish ethical teachings. The Samaritan of the parable forfeits safety and convenience to save a wounded Jewish robbery victim after Jewish authorities had seen the same victim and walked by on the other side of the road. By insinuating that the Samaritan was something of an "honorary Jew"--and indeed a better Jew than those who passed by the victim--Jesus was by no means attempting to insult the Samaritan. By insisting that Martin Luther King was not a Christian but rather an exemplary inheritor of Hitchens-like secular modernist values, Hitchens bestows on King a similar kind of ethnocentric honor. It is thus pointless to be too offended on King's behalf.