Bully story

So I was watching CNN, and besides the tsunami calamity, there was footage of a kid beating up another in class. I dislike conflict, and it's hard to push my buttons. But seeing stuff like this activates a switch. I feel enraged, and want to punch the bully out. Teacher too for that matter, don't know what the hell he was doing.

I can't understand why I feel like this. Although I dislike conflict, I can become just as vicious. Is that normal?