Social media have carried a raft of posts inciting Palestinians to violence against Israel, and several perpetrators of recent attacks are known to have received and promoted such propaganda. Micah Lakin Avni, whose father Richard Lakin was shot and stabbed by terrorists on a Jerusalem bus last month, believes something can be done about the problem:

The young men who boarded the bus that day intent on murdering my seventy-six-year-old father did not make their decision in a vacuum. One was a regular on Facebook, where he had already posted a “will for any martyr.” Very likely, they made use of one of the thousands of posts, manuals, and instructional videos circulating in Palestinian society these last few weeks, like the image, shared by thousands on Facebook, showing an anatomical chart of the human body with advice on where to stab for maximal damage.

Sickeningly, my father, too, became a viral hit on Palestinian social media: hours after he was shot and stabbed, a video re-enactment of the attack was posted online celebrating the gruesome incident and calling on more young Palestinians to go out and murder Jews. Such images, YouTube videos, and comments have become a regular feature on social media after every attack. . . .

Just as it is universally recognized that shouting fire in a crowded theater is dangerous and should be prohibited, so, too, must we now recognize that rampant online incitement is a danger that must be reckoned with immediately, before more innocent people end up as victims.

One immediate solution is to remove blatant incitement without waiting for formal complaints—it’s one thing to express a political opinion, even one that supports violent measures, and another to publish a how-to chart designed to train and recruit future terrorists. . . . I believe that any truly successful effort to curb the culture of hate on social media must come from the companies themselves. . . . Companies can and must work harder—using all the tools at their disposal—to create an online culture that does not tolerate violence and hate.

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.