Ask the British Labor-party leader Jeremy Corbyn, or his sympathizers, why he is so fixated on Israel’s supposed misdeeds, and you’ll no doubt hear about his abiding commitment to Palestinians’ human rights. To polish his image as a defender of Muslims, notes Fiyaz Mughal, he scarcely misses an opportunity to be photographed taking part in a Ramadan celebration or other Muslim event. Yet he is a stubborn defender of the former Serbian president Slobodan Milosevic, who took part in a genocidal campaign to “cleanse” Bosnia of Muslims, and was engaged in similar efforts against the Muslims of Kosovo when the U.S. and its allies intervened. Years later, Corbyn even introduced a motion in parliament praising one John Pilger for writing an article defending Milosevic. (Free registration may be required.)

Over 800,000 Kosovar Muslims were displaced [in 1999]. Kosovar Muslim men, women, and children were murdered in a systematic manner; hundreds of people disappeared, only to be found dumped in shallow graves with gunshot wounds and brutal fresh scars—evidence of torture. [Yet Pilger’s] piece ended with a dismissal of the then-ongoing trial of Milosevic for war crimes as a “farce” and a “show trial” of a man whose only crime was his refusal to “surrender sovereignty” to the demands of global finance organizations. Needless to say, Pilger, together with fellow journalist Seymour Hersh, is also a leading light among apologists [for another mass-murderer of Muslims, Syria’s] Bashar al-Assad.

But give [Corbyn] a photo opportunity at a mosque and he is there looking like the “magic grandpa” of his fans’ online iconography, surrounded by young Muslims who know little about his political history and how little his solidarity with Muslims in danger is really worth.

And then there is Corbyn’s solidarity with Iran, on whose government-run English-language television channel he has made innumerable appearances:

Muslims like me, willing to criticize, challenge, and reflect on some Muslim observances and practices, and opposed to enforced religious observance, would not stand a chance in Iran. We would be arrested, tortured, or killed. So how has Corbyn “challenged” the Iranian regime’s human-rights record and its determined assault on “disobedient” Muslims, even at the cost of their lives? In 2014, . . . Corbyn praised the “tolerance and acceptance of other faiths, traditions, and ethnic groupings in Iran.”

And when Islamic State, another leading killer of Muslims, launched a terror attack on Egyptians in the Sinai, Corbyn naturally blamed the Jewish state. After all, writes Mughal, “all roads in his conspiratorial mindset lead to Israel.”

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.