In the last decades of the 19th century, reports began to appear in medical and scientific literature that there was a disproportionately high incidence of diabetes—a disease still little understood—in Jews. Based on modern medical knowledge, there is reason to speculate as to why this might have been true. But, writes Arleen Marcia Tuchman, the data are largely suspect, and might reveal more about the authors than the patients:

For one, most writers who mentioned this link [between Jews and diabetes] rarely provided statistics to back up their claims. They simply repeated what everyone else was saying. And those who did offer up numbers and patterns offered statistics that were often unreliable. Not only did physicians usually draw on select populations, whether from their own private practice, the patient population of a specific hospital, or those seeking relief at expensive spas, but it was not always clear how to determine whether someone was Jewish—especially when calculating mortality rather than morbidity rates.

Some of [the contemporary suggestions about a Jewish predisposition to diabetes] were decidedly antagonistic toward Jews. J.G. Wilson, a surgeon with the U.S. Public Health Service, was particularly disdainful. In a study he conducted on “Jewish psychopathology,” . . . he referred to Jews as “a highly inbred and psychopathically inclined race.” Wilson made this claim while he was stationed at Ellis Island, the U.S. port of entry for most East European Jews. His sense of discomfort with [with Jews was apparent in] his insistence that Jews had such a high rate of this disease because of “some hereditary defect” exacerbated by “the practice of inbreeding.”

The hostility that Wilson evinced in his discussion of Jews and diabetes was, however, the exception rather than the rule. Far more common in the diabetes literature was subtle trafficking in negative stereotypes. Thus one physician attributed Jews’ high rate of diabetes to the love of the “Hebrew race” for “high living,” adding that “they are given to parties, they congregate together and have frequent and irregular meals.” William Osler wrote of Jews’ particularly “neurotic temperament.” A journalist weighed in, blaming Jews’ “racial tendency to corpulence.” And Haven Emerson, professor of preventive medicine at Columbia’s College of Physicians and Surgeons, and a previous commissioner of health for the city of New York, put the onus on Jews for spreading what he called “this great luxury disease.”

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.