The world has been reeling in the wake of the Oct. 7 terrorist massacre that left over 1,400 people dead in Israel. There has also been tremendous pain and loss of life on the Palestinian side in Gaza. Trying to understand the public’s reaction to the terrorist attack has been a challenging process. Hamas’s barbaric and reprehensible attacks included beheadings, kidnapping, rape, and indiscriminate slaughter of elderly civilians, women, children, and babies. So, most of the public naturally reacted with shock, outrage, and fear.

But some were conspicuously celebratory. Using terms like “decolonization” and sharing images of paragliders on social media, many on the political left are not simply remaining silent in the wake of terrorism; they are actively endorsing it. On American university campuses, Ivy League professors praised Hamas’s “awesome victory” and called it “exhilarating” and “energizing.” Students shouted, “Glory to the martyrs!”

While this may express antisemitism, I don’t think that’s the whole story. Psychological science can offer some additional clues. Researchers who study moral psychology offer a theory called dyadic morality. According to it, people use mental prototypes. For instance, if I say “dog,” people can easily imagine one with commonly shared features such as four legs, fur, and barking. A similar psychological process unfolds when thinking about unethical behaviors. For instance, when considering assault with a deadly weapon, people imagine an immoral agent (the attacker) carrying out the action against a moral patient (the attacked). As the authors of one paper put it, “Good or evil-doers typically require a recipient to help (for good) or harm (for evil). Villains require victims to harm, and heroes need those same victims to rescue.” Antisocial actions like theft, rape, or murder are only considered unethical in a case where an actual victim is harmed by a perpetrator. But if the attacked person is not considered a victim, then there is nothing immoral about those actions.

The ghoulish reactions to the massacre in Israel revealed that many progressives are incapable of applying the victim template to Israelis or the perpetrator template to Palestinians. In their worldview, Israelis are always attackers, and Gazans are always attacked, never the reverse, no matter what actions are involved. Other commentators have made parallel observations and similarly concluded that many progressives seem unable to comprehend that minority groups who have experienced inhumane treatment can also have agency or that majority groups with powerful militaries can also be mistreated. This perversion of moral typecasting is a psychological and ethical failure.

Some argue that people’s reactions to an atrocity should not get more attention than the atrocity itself, to which I agree. Others dismiss these reactions as a minor nuisance not worth paying much attention to at all, to which I’m afraid I have to disagree. If we’re not careful, what begins as secondary reactions to a bloodbath end up becoming something much more dangerous.

The tragedy did not end on Oct. 7. It continued when Jewish people in Berlin had their houses marked during Hamas’s call to jihad or when a crowd of Australians chanted, “Gas the Jews.” When we yield to extremist voices glorifying violence where we live, we have lost our own moral compass. These fanatic views, however sporadic, must be held in check. And we would be wise to pay attention to exactly who defends or justifies such carnage. Listen to the ones who proclaim it is right for Hamas to decapitate babies because they are “settlers.” People are unmasking themselves now, and we shouldn’t look away.

Saner liberal voices are practically begging Israel not to make the same mistake as Hamas in its military response and not to seek revenge. Even an Israeli survivor of the Oct. 7 attack is calling on her government to make peace and spare Gazans from a worse fate. The sibling of someone killed is saying publicly that his brother’s death should not be used to justify killing innocent people in Gaza. Muslims are also reckoning with this horror.

This is the moral clarity we need. This shows that even people who are victims of terrorism can still empathize with the people who supported the attack and still hold a functioning ethical blueprint. We must organize our actions around recognizing that every human can both perpetrate and suffer. We all have the capacity to be moral agents and patients.