You know, I have lots of tropical fish tanks in my house, and I observe how they act and behave. It's very interesting, for example, in a cichlids tank, when you scare the big fish, it gets mad and since they know they cant attack you back, they start picking at the smaller fish because they're frustrated.
Well it's the same for teachers at school: since they cant use of their dictatorship on the openly annoying kids in class, they'd rather put pressure over the kids who appear different and who wouldnt talk back to the teachers, or who wouldnt act stupid and start being violent.
I heard at the tv news the other day that the teachers here would start forbidding some kids to dress in a provocative way, like goths! yeah right, as on the other side, some other kids who dress in sports cloths can get guns in their pants, those kids are O.K. huh? Damn cowards...