I just can't for the life of me wrap my mind around gunning down innocent people, much less kids. I think most people can imagine a scenario where they could be mad enough to kill someone. Those scenarios likely vary widely from person to person, but pushed far enough, most people would eventually bust a cap on a mother fucker. What I can't imagine is just opening fire on random people. Why? I think that's what makes things like this so hard to understand, sane people simply can't.