As you're already obviously aware, a highly-deluded Men's Rights Activist (redundant) killed several random women for not sleeping with him. I don't know of a better way to summarize it than with that seemingly incomprehensible sentence. I say that sentence is incomprehensible because it shouldn't be a sentence that exists and it should make no sense, but unfortunately it's exactly what happened. Even more unfortunate is the number of men who are earnestly arguing this is why women should sleep with any man who asks, walks by them, or just exists, apparently.
There's already been about a thousand different think pieces written on this, but this one is probably the best I've read. It's short and very well written, so I highly suggest you go take the three minutes necessary to read it. I'll wait. Done? Good. I really like how Dr. McDevitt highlights the impossible double standard young women (well, all women, but especially young women) in our society face: if you do have sex with men, you're a stupid whore who deserves to be bullied to death; if you don't have sex with men, you're a stupid controlling bitch who deserves to die for being withholding (if you're a woman who has sex with other women, you're allowed to film it for the pleasure of men, but you should be denied all civil rights, if I understand the argument correctly).
What I would like to selfishly add to the conversation is that this is why discourse matters, why fighting against misogyny in all its forms matters, and frankly, why sociology matters. Because analyzing the incredibly toxic form of masculinity subscribed to by these MRA types is exactly what sociology does, but it's also exactly the kind of thing that creationists* use to mock sociology as a useless discipline. "Why would you bother studying this and taking these people seriously? They're just some losers on the internet. Only people with nothing better to do with their time would think this is worth talking about." I've gotten that exact response from all sorts of people when discussing these kinds of issues, the idea that how people talk about things doesn't matter, and that if someone is espousing reprehensible garbage we can simply ignore them and they'll go away.
But such a position fails to understand how important discourse is in creating real, material social effects. For a dramatic example, see John Hagan's work on how racial discourse was used to spur the genocide in Darfur. In this case, it's extremely clear how the toxic discourse and ideology of the men's rights movement strongly contributed to, if not caused, this horrible tragedy. As much as anyone may want to blame this on mental illness (whenever white people kill someone, it's always because of mental illness), it's simple empirical fact the vast, vast majority of people with mental illness never harm anyone (in fact, they are far more likely to be harmed themselves). Even if there is some magical psychological cause is found to be behind this, the particular form such murderous rage took was unequivocally influenced by this loose collective of men who feel women are unfairly controlling them and deserve retribution for their unforgivable crime of not fucking any man who wants them.
And that's why studying (and fighting against) these horrible forms of discourse is important and necessary. Because they're not just words, they're words that clearly direct people to action. And this particular murder spree is far from an isolated case -- in fact, that very same night, three men fired eight rounds at a fleeing group of women who had refused to have sex with them. I could go ahead and link to about a thousand similar stories, but it's too depressing and you have google. But please do remember this the next time someone claims a social issue is not important and we should just all ignore it.
*I've encountered far too many people, even highly educated people, that just dismiss the entire field of sociology out of hand, with essentially no knowledge of what sociology even is. They're using the same logic of creationists -- they either don't understand or don't like what sociologists have to say (or both), so they just claim it's not real. I've taken to referring to them as creationists, because most educated people rightly take that as an insult. But science deniers are science deniers, regardless of the specific science they're denying.