In one of Pierre-Auguste Renoir’s best-known paintings, a bearded man in a top hat stands behind most of the other figures, with his back toward the viewer and his face partially obscured. Experts, along with many of Renoir’s contemporaries, have identified this man as the Jewish art critic and art collector Charles Ephrussi. Menachem Wecker writes:

Born in 1849 in Odessa, Ephrussi came from a wealthy Jewish family, which made its money in grain exporting and banking. By the 1870s, he was living in Paris, and anti-Semitism was on the rise. . . .

Ephrussi first collected Italian Renaissance works. . . . He was also interested in Japanese art, newly fashionable in Paris at the time. . . . At age twenty-eight, he debuted as a writer for the Gazette des Beaux-Arts, where he would remain for nearly 30 years, [eventually] as co-owner and director. . . .

Ephrussi rubbed elbows with Parisian elite and his reputation as an art historian grew, but he was nevertheless treated unfairly. . . . Edmond de Goncourt, [a] French man of letters, . . . wrote, “Ephrussi the Jew went to six or seven parties a night, so that he could climb to a position at the Ministry of Fine Arts.” And the English author George Painter, who was Marcel Proust’s biographer, recorded that people made fun of Ephrussi’s “Polish Jewish” accent. . . .

Not only did Ephrussi buy work from the Impressionists and write about them, but he also “won over” other clients for the Impressionists. [He] helped Renoir in particular find buyers in the French Jewish community. . . . But Renoir too would write in an anti-Semitic manner about Ephrussi, and their relationship [subsequently] cooled.

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.