Rodger was very clear about the reasoning behind his violence. In a video posted online before the shooting, he says:
For the last eight years of my life, ever since I hit puberty, I’ve been forced to endure an existence of loneliness, rejection and unfulfilled desires. All because girls have never been attracted to me. Girls gave their affection and sex and love to other men, but never to me. I’m 22-years-old and still a virgin. I’ve never even kissed a girl. I’ve been through college, for two and a half years, more than that actually, and I’m still a virgin. It has been very torturous.
College is the time when everyone experiences those things such as sex and fun and pleasure. But in those years I’ve had to rot in loneliness. It’s not fair. You girls have never been attracted to me. I don’t know why you girls aren’t attracted to me. But I will punish you all for it. It’s an injustice, a crime because I don’t know what you don’t see in me.
This is male entitlement. You’re looking at it.
Rodger was so enraged that he had not been given that which he deserves, as a man — sexual access to women — that he killed.
In a world wherein men learn they not only deserve, but have the right to women’s bodies, Rodger’s behaviour isn’t really all that surprising. From the time they are young, boys are offered women’s bodies. They are provided with pornography, told that this is what women are for: your eyes, your pleasure, your dick. Read more.