A lot of effort goes into "debunking" conspiracy theories, and certainly there are many which are absurd, and poorly defended. But the tendency to find conspiracies to explain events, is anything but rooted in ignorance.
The tendency to skepticism is not always a sign of intelligence. Sometimes, when otherwise intelligent people dismiss the connection between a square peg and a square hole, it's because they've been conditioned to ignore it. I believe this is the case with much of the self-proclaimed intellectual elite's disdain for so-called "conspiracy theories"; people have to be taught, or otherwise pressured not to see the pattern.
A person who holds a conspiratorial world view, is generally a person who demands that the world make more sense than he's told it does. They're someone looking for the laws of cause and effect, the fit between square peg and square hole, the connectable dots, to justify a narrative which makes more sense to them than something that doesn't make sense to them. Now while one may in fact be so stupid, that ordinary events are inexplicable, the events which generate conspiracy theories do not usually fall into that category; they are attempting to explain extraordinary events.
We use the concept of conspiracy every day in our legal system, and there would be many thousands more criminals walking our streets were we not to recognize and include the concept of conspiracy in trials. Yet somehow, a vastly different standard has been applied to certain historic crimes over the decades when the public demands a logical explanation for the extraordinary events in question.
Self-proclaimed debunkers pull out every trick in the book to discredit the now flourishing "9-11 Truth movement"; pointing out the most improbable theories as though they were representative (straw men), pointing out the unrelated UFO believers who may also believe them, all in an attempt to portray "idiocy by association" and to make a soup so thick with the stench of lunacy, that anyone who dares tread in it is sullied by association.
But governments exist as defacto conspiracies to control their peoples, it's only a question of which people need to be controlled. The government of North Korea exists to protect itself and control it's population by keeping them in the dark through continual disinformation. The governments of China, The United Kingdom, Canada, and the United States, all have one thing in common; despite varying in the availability of information, they all exist as rival nations with militaries, presumably military strategies, and a requirement to keep their own people in the dark to one degree or another if their long term global military strategy has any chance of succeeding. All one needs to understand about so-called "conspiracy theories" is that the only thing in any question when dealing with a nation of significance on the world stage, is which particular theory fits the conduct. The conspiracy is a given. But the requirement of secrecy can manifest itself overtly as in the case of China, or more artfully in the case of the United States; one nation will take you out and put a bullet in your head for questioning the regime, the other will simply create a culture of derision for those who dare to ask the wrong question in the midst of plenty. It's no coincidence then, that peoples outside any particular country can more clearly see the dark side of a nation's agenda than those within it; the Chinese government's primary motive is to lie about it's own ambitions, just as the United States is. Both the Chinese and American people probably get the truth more often than not about each other respectively if the truth is damning of the other, and almost never if it's good.
Another frequent charge laid against the conspiratorial world view is that conspiracies of such magnitude take too many people to be probable or even possible. Nothing could be further from the truth; they actually take remarkably few people. I'd like to use the American space program as a good example. To the unthinking, it's simply the space program, and any given launch of the shuttle has it's purpose in nothing much further than the idea that man has an innate desire to explore. But applying the conspiratorial view point paints a far more accurate picture of reality; the space program is in fact a quest by the United States to control the space above the earth for military purposes, and any so-called civilian purposes, are only there for public relations purposes. Now NASA is a conspiracy: how many day to day people are "in on it" in the usual understanding of the term? Possibly none. No one needs to be in on it within the agency itself because the autocratic power structure of the organization and it's controlling overseers precludes -or at the very least- does not require each individual from knowing the entire mission; they only need to know their job. The planners in the Pentagon, unseen and un-elected are now free to engage the macro conspiratorial benefits of the plan, and the workers are simply people doing their job who mind their own business if they'd like to keep it. Such I believe was the case with 9-11; a veritable handful of people in an autocratic top-down human structure, decided to facilitate the event. The average New York Port Worker who thought it was suspicious that certain policies were being changed, that cameras were turned off as the WTC was "powered down" before the attacks only had the choice to believe it was perhaps curious, or to ask questions and put their job in jeopardy. This isn't complicated. Like a NASA employee, he decides it's none of his business, and of course once the crime has gone down, it's no trick to make him lay awake in fear should he talk to anyone about the "problems" he saw.
The individuals who participate in deriding so-called conspiracy theorists, are generally of two ilk; those who've been manipulated into it through what is commonly referred to as 'peer pressure', and those who's rabid nationalism is held as a higher value than any possibility that their nation just might not be the paradigm of moral virtue in a sea of evil that the evidence tells them it isn't. Some of these people may even act as conscious gate-keepers if they're individually corrupt enough as "party loyalists".
Any decent sleuth who witnesses a crime and wants to solve it however, begins with an open mind and a first question; who stood most to gain from the crime? Applying this question to September 11th generates some very immediate exclusions, first among them being the Arab world, followed by an immediate inclusion: an aging super-power which has exhausted it's previous colonizations of treasure and which has suddenly found itself uncomfortably at peace.
Public opinion outside the United States is statistically overwhelming of the view that the attacks of September 11th were an inside job. It's not that the rest of the world is worthy of being labeled "paranoid" that they should have arrived at such a consensus. They are simply not subject to the social forces and media which would prevent such a first question and conclusion.
It is thus that we arrive at the mother of all conspiracies; the myth of American democracy. It's never existed apart from an onslaught of propaganda which claims otherwise. It's only a feel-good story line accepted by most people because they're comfortable amid the wealth generated by it's undemocratic foreign policy. As usual, the people with the most are the people which have the most to lose by questioning the regime. There's no need for a conscious conspiracy, not when an unconscious or negligent complicity with the status quo will suffice. It will and it does.
The culture of derision against the conspiratorial world view has real consequences today. If 9/11 was in fact the inside job so much evidence indicates that it was, unless that evidence is taken seriously, we risk continuing down a path that has no basis in reality. Self-proclaimed debunkers are fond of the axiom "Extraordinary claims require extraordinary proof". If this is true, then do not extremely serious accusations warrant extremely serious investigations? But the majority of Democrats and independent voters in this country who oppose the innumerable abuses of power undertaken by the Bush administration are in fact only hurting themselves when they fall victim to the debunker's tactics to dissuade them from further examining the evidence for government complicity. They want a new administration, but one competent to carry out the "war of terror". This is the strict equivalent of the people of NAZI Germany who opposed Hitler, wanting a new leader to deal with the Jew's burning of the Reichstag. The bottom line on 9-11 is that if you don't know the truth, everything you do based upon the lie is going to be dead wrong.