When Santa Barbara police arrived at Elliot Rodger’s apartment last month—after Rodger’s mother alerted authorities to her son’s YouTube videos, where he expressed his resentment of women who don’t have sex with him, aired his jealousy of the men they do choose, and stated his intentions to remedy this “injustice” through a display of his own “magnificence and power”—they left with the impression that he was a “perfectly polite, kind and wonderful human.” Then Rodger killed six people and himself on Friday night, leaving a manifesto that spelled out his virulent hatred for women in more explicit terms, and Santa Barbara County Sheriff Bill Brown deemed him a “madman.”

Another rude awakening played out on social media this weekend as news of Rodger’s attack spread around the world. When women took to Twitter to share their own everyday experiences with men who had reduced them to sexual conquests and threatened them with violence for failing to comply—filing their anecdotes under the hashtag #YesAllWomen—some men joined in to express surprise at these revelations, which amassed more quickly than observers could digest. How can some men manage to appear polite, kind, even “wonderful” in public while perpetuating sexism under the radar of other men’s notice? And how could this dynamic be so obvious to so many women, yet completely foreign to the men in their lives? Some #YesAllWomen contributors suggested that men simply aren’t paying attention to misogyny. Others claimed that they deliberately ignore it. There could also be a performative aspect to this public outpouring of male shock—a man who expresses his own lack of awareness of sexism implicitly absolves himself of his own contributions to it.

But there are other, more insidious hurdles that prevent male bystanders from helping to fight violence against women. Among men, misogyny hides in plain sight, and not just because most men are oblivious to the problem or callous toward its impact. Men who objectify and threaten women often strategically obscure their actions from other men, taking care to harass women when other men aren’t around.

The night after the murders, I was at a backyard party in New York, talking with a female friend, when a drunk man stepped right between us. “I was thinking the exact same thing,” he said. As we had been discussing pay discrepancies between male and female journalists, we informed him that this was unlikely. But we politely endured him as he dominated our conversation, insisted on hugging me, and talked too long about his obsession with my friend’s hair. I escaped inside, and my friend followed a few minutes later. The guy had asked for her phone number, and she had declined, informing him that she was married and, by the way, her husband was at the party. “Why did I say that? I wouldn’t have been interested in him even if I weren’t married,” she told me. “Being married was, like, the sixth most pressing reason you weren’t into him,” I said. We agreed that she had said this because aggressive men are more likely to defer to another man’s domain than to accept a woman’s autonomous rejection of him.

A week before the murders, I experienced a similar dynamic when I went for a jog in Palm Springs, California. It was early on a weekend morning, and the streets that had been full of pedestrians the night before were now quiet. When I paused outside a convenience store to stretch, a man sitting at a bus stop across the street from me began yelling obscene comments about my body. When my boyfriend came out of the convenience store, he shut up.

These are forms of male aggression that only women see. But even when men are afforded a front seat to harassment, they don’t always have the correct vantage point for recognizing the subtlety of its operation. Four years before the murders, I was sitting in a bar in Washington, D.C. with a male friend. Another young woman was alone at the bar when an older man scooted next to her. He was aggressive, wasted, and sitting too close, but she smiled curtly at his ramblings and laughed softly at his jokes as she patiently downed her drink. “Why is she humoring him?” my friend asked me. “You would never do that.” I was too embarrassed to say: “Because he looks scary” and “I do it all the time.”

Women who have experienced this can recognize that placating these men is a rational choice, a form of self-defense to protect against setting off an aggressor. But to male bystanders, it often looks like a warm welcome, and that helps to shift blame in the public eye from the harasser and onto his target, who’s failed to respond with the type of masculine bravado that men more easily recognize. Two weeks before the murders, Louis C.K.—who has always recognized pervasive male violence against women in his stand-up—spelled out how this works in an episode of Louie, where he recalls watching a man and a woman walking together on a date. “He goes to kiss her, and she does an amazing thing that women somehow learn how to do—she hugged him very warmly. Men think this is affection, but what this is is a boxing maneuver.” Women “are better at rejecting us than we are,” C.K. said. “They have the skills to reject men in the way that we can then not kill them.”

When Elliot Rodger finally snapped, he drove to a Santa Barbara sorority house as part of his plan to give the “female gender one last chance to provide me with the pleasures I deserved from them,” and killed two women who were walking outside. Before he hit the sorority house, he stabbed three men in his apartment; after he left the sorority, he killed another man who was entering a nearby convenience store. In the course of the attack, he wounded 13 more people. Rodger hated all the women who did not provide him sex, but he also resented the men he felt had been standing in the way of his conquests, though they were never made aware of this belief. (Many men die of domestic-violence-related murders this way, killed by ex-boyfriends, ex-husbands, and family members of the women in their lives.) Some men are using this death count to claim that Rodger’s killings were not motivated by misogyny, but that is a simplistic account of how misogyny operates in a society that privately abides the hatred of women unless it’s expressed in its most obvious forms.

Read the rest of Slate’s coverage of the UC­–Santa Barbara shooting.