IMO, it's never the fault of the kids. It's the fault of the parents, the teachers, and the administrators. They are all too lazy, evil, entitled, or stupid to do the things that are necessary to help kids feel safe at school. Half of them don't even really see it as a problem.

When I look back on my bullies in school I just see a bunch of messed up kids that were given too much leeway to hurt other kids because adults didn't want to take the time or effort to actually raise and supervise them.