Women have had enough. The stares. The butt-grabs. The little comments. And now this: a man writes a 140-page misogynist manifesto before killing six people, and yet – still – women are called hysterical for insisting this tragedy was driven by sexism.

In the days since Elliot Rodger murdered six people in Isla Vista, California, citing hatred of women and sexual rejection as the reason for his rampage, women across the world have come out en masse to share their stories of everyday sexism and misogyny – and to tell the world that enough is enough. On Twitter, Tumblr and on the streets, women laid bare just how pervasive sexism still is, and shot back against detractors desperate to believe that misogyny had nothing to do with the Rodger rampage.

The reason women mobilized so quickly after the shooting is because we recognized immediately the language and ideology in Rodger's videos and manifesto: the over-the-top sexual entitlement; the rage against women who "dared" to reject him; the antiquated, but nonetheless terrifying, belief that women should not be in control of their own sexual choices. Regardless of Rodger's mental health issues – which we still don't know much about – his ideas were not "crazy" by the standards of the world today. They are the norm.

So students protested in a walk to Rodger's apartment holding signs with slogans like, "Nobody is entitled to a woman's body". A new Tumblr, When Women Refuse, listed story after story of women who suffered violence after rejecting a man's sexual advances. And the Twitter hashtag #YesAllWomen went viral as hundreds of thousands of people shared their experiences with misogyny.

In addition to being a response to the frustrating "not all men" narrative that preceded Rodger's killing spree, #YesAllWomen tried to illustrate the ubiquity of sexism in women's lives. For instance, writer and sex educator Kendall Mckenzie tweeted, "When women trust men, we're naive idiots who should've known better. When women fear men, we're hysterical, paranoid feminazis." Imani Gandy, the senior legal analyst at RH Reality Check also known as @AngryBlackLady, wrote "#YesAllWomen never leave their drink unattended at a bar or a party." And feminist writer-activist Soraya Chemaly tweeted out, "#YesAllWomen because it's 2014 and men continue to shoot girls and throw acid on them because they don't want them to go to school."

The simple act of women sharing their experiences and thoughts became an international conversation, but it also inspired backlash.

For every incredible person sharing his or her story on #YesAllWomen, there seemed to be another person doubting its necessity: angry men insisted that Rodger's violence couldn't have been about sexism because four of the six people killed were men. But those men were as much victims of Rodger's misogyny as the women he hurt and killed – women aren't the only ones hurt by hateful ideology. Arguing anything else is willful ignorance.

As journalist Lindsay Beyerstein wrote on her Facebook page, it's infuriating for people to pretend "that there's some deep mystery about why Elliot Rodger did what he did, or worse, that there's something unseemly or self-serving about feminists pointing out that he was an explicitly misogynist terrorist." She continued:

Rodger told the world exactly why he went on this killing spree. He spelled it out in excruciating detail and sent his narrative of the killings to the media. In case that wasn't enough, he made a series of YouTube videos to cement his narrative of his own crime in the public mind.

Truly, he couldn't have made it any clearer. Why do some people nonetheless doubt his laid-out, explicit motive?

Part of the obstinate disbelief seems to be a need to protect the privileges of sexism: associating misogyny with a mass murder would mean having to recognize just how dangerous misogyny really is and - if you're partaking - giving it up. Some men want to believe that they can continue to call women "sluts" and make rape jokes without being part of a broader cultural impact. But they can't: sexism, from everyday harassment to inequality enshrined in policy, pollutes our society as a whole and limits our ability to create real justice for women.

Someone asked me over the weekend if I thought this shooting - and the aftermath of activism - would be a watershed moment. I replied that I was hopeful, and I still am, because being cautiously optimistic is the only way I'm able to do this work and get up in the morning. But I'm also exhausted, and fed up.

If this shooting isn't the clearest example of sexism turned deadly - then what is? What will it take for Americans to get real about how profoundly misogynist our country really is?

I hope this activism in the wake of such a tragedy will mean a sea change on sexism and not just a momentary pause in the misogyny that pervades our culture. I want to believe that the men tweeting support of #YesAllWomen will take their activism to the streets and their homes and their representative's offices as often as they do on Twitter. As Richard Martinez - whose son Chris was killed in the attack - said, "Get to work and do something."

I want to believe that a misogynist shooting people dead in the street will matter to people for more than the length of the news cycle. And that when said shooter explains that his motivations is as simple as a profound hatred for women, that we believe him.