Read the parent of my comment. I was addressing bullying.
But yeah, it's true. One could argue that the school shooter was doing this for himself, which of course isn't something I'd wish on anyone. I think that these teenagers feel helpless, without any purpose in life. I'm not saying it's the worst time to be alive, but the mass appeal of no-religion, being agnostic is a real problem. I even doubt if I should continue being agnostic at times. Every once in a while I lose purpose and really haven't found a good way to cope with it.
Generally speaking, I think the cause of these shootings comes down to the feeling of helplessness and not feeling useful to society.