You could fill many little red books with the words written about the U.K. Labor party’s anti-Semitism problem since the socialist Jeremy Corbyn became the party’s leader four years ago. As Tanya Gold writes, it is “obvious that anti-Semitism has been slowly overwhelming Labor.” And yet Corbyn and his allies continue to deny that fact, hurling slurs at anyone who dares point it out.

The most recent chapter in this depressing story involves a BBC documentary about the scandal, which added party insider testimony and texture, and which the party is attempting to suppress:

Panorama investigators had new material: testimony from non-Jewish Labor staffers who worked in Labor’s complaints department, which is supposedly entirely independent of the leadership. Eight former members of staff were interviewed, four of whom broke nondisclosure agreements to do so. Although Labor, which is, after all, supposed to be the party of laborers, generally supports whistle-blowers, it is currently threatening its former employees with legal action.

The response to the testimony given on Panorama was as interesting a lesson in pathological denial as the program itself. . . . The Labor press team tweeted this denial: “These disaffected former officials include those who have always opposed Jeremy Corbyn’s leadership, worked actively to undermine it, and have both personal and political axes to grind. This throws into doubt their credibility as sources.”

The story continues to unfold, writes Gold, because

Corbyn cannot conceive of himself as a racist. He has no aptitude for self-reflection and, in the impact of his own incompetence, he sees only the sabotage of his enemies. His mantra is: “I oppose anti-Semitism and all forms of racism.” The second part reads like a rebuke to a Jewish minority that supports a “racist state” and will not share the Shoah.

Corbyn did issue a seemingly strong statement about anti-Semitism in the party last week. But at this point who can believe him?

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.