Having feelings of revenge and rage torward women and acting on them are two very different things. While it's crucial to identify aspects of rape culture in actions that aren't actual rape, well, those actions aren't actual rape, so it's important to identify that, too.
Tragedies like this always feel like sorta of swiss cheese with the holes aligned kind of thing, as society does have a lot of safety nets against someone going into a murderous rampage over these feelings: from education teaching you that those feelings are wrong, going through religion teaching you that something better is on the afterlife, to something going on right on people's life that he is not willing to sacrifice that because of what is going wrong, etc etc.; anything that prevents you from doing this is a a safety net, and to somehow slip through the cracks of all of them takes a conjunction of factors. And people will go on like "if only he had better parenting"; "if only he wasn't sick in the head"; "if only he had religion"; "if only he wasn't taught that feminism is bullshit", etc etc.; but I think the fact is that all of those are potentially right and none of them are ultimately the answer. Something should have held it back, again, society has a lot of things in place to hold you back, all of them failed.
And I think Sunny is right, not enough shame on this people, shaming people for believing they are entitled to other people's body/feelings is one of those safety net. Having an internet community that tells you it's all right to hate on other people removes one of those safety nets.
.