Notably, none expressed concern at the media mauling of a left-wing, satirical Jewish group called Jewdas when Corbyn was widely attacked for meeting "the wrong kind of Jews". In fact, leading Labour figures, including the Jewish Labour Movement, joined in the abuse.
And increasingly in this febrile atmosphere, there has been an ever-greater indulgence of the "right kind of anti-semitism" when it is directed at Corbyn supporters.
A troubling illustration was provided on the TV show Good Morning Britain this week, when Tom Bower was invited on to discuss his new unauthorised biography of Corbyn, in which he accuses him of anti-semitism. The hosts looked on demurely as Bower, a Jewish journalist, defamed fellow Jewish journalist Michael Segalov as a "self-hating Jew" for defending Corbyn on the show.Revenge of the Blairites
So what is the significance of the fact that the Labour MPs who have been most outspoken in criticising Corbyn those who helped organise a 2016 leadership challenge against him, and those who are now rumoured to be considering joining the breakaway faction are heavily represented on the list of MPs supporting LFI?
For them, it seems, vigorous support for Israel is not only a key foreign policy matter, but a marker of their political priorities and worldview one that starkly clashes with the views of Corbyn and a majority of the Labour membership.
Anti-semitism has turned out to be the most useful and damaging weapon to wield against the Labour leader for a variety of reasons close to the hearts of the holdouts from the Blair era, who still dominate the parliamentary party and parts of the Labour bureaucracy.
Perhaps most obviously, the Blairite wing of the party is still primarily loyal to a notion that Britain should at all costs maintain its transatlantic alliance with the United States in foreign policy matters. Israel is a key issue for those on both sides of the Atlantic who see that state as a projection of Western power into the oil-rich Middle East and romanticise Israel as a guarantor of Western values in a "barbaric" region.
Corbyn's prioritising of Palestinian rights threatens to overturn a core imperial value to which the Blairites cling.Tarred and feathered
But it goes further. Anti-semitism has become a useful stand-in for the deep differences in a domestic political culture between the Blairites, on one hand, and Corbyn and the wider membership, on the other.
A focus on anti-semitism avoids the right-wing MPs having to admit much wider grievances with Corbyn's Labour that would probably play far less well not only with Labour members, but with the broader British electorate.
As well as their enthusiasm for foreign wars, the Blairites support the enrichment of a narrow neo-liberal elite, are ambivalent about austerity policies, and are reticent at returning key utilities to public ownership. All of this can be neatly evaded and veiled by talking up anti-semitism.
But the utility of anti-semitism as a weapon with which to beat Corbyn and his supporters however unfairly runs deeper still.
The Blairites view allegations of anti-Jewish racism as a trump card. Calling someone an anti-semite rapidly closes down all debate and rational thought. It isolates, then tars and feathers its targets. No one wants to be seen to be associated with an anti-semite, let alone defend them.Weak hand exposed
That is one reason why anti-semitism smears have been so maliciously effective against anti-Zionist Jews in the party and used with barely a murmur of protest or in most cases, even recognition that Jews are being suspended and expelled for opposing Israel's racist policies towards Palestinians.
This is a revival of the vile "self-hating Jew" trope that Israel and its defenders concocted decades ago to intimidate Jewish critics.
The Blairites in Labour, joined by the ruling Conservative Party, the mainstream media and pro-Israel lobby groups, have selected anti-semitism as the terrain on which to try to destroy a Corbyn-led Labour Party, because it is a battlefield in which the left stands no hope of getting a fair hearing or any hearing at all.