None of us are capable of living without a mediator. Without tons of people standing between us and the truly bad guys, we'd all be made into bitches in no time. It is first world as hell to forget that.
Also, we're talking about physical violence, not run of the mill shit talk. Punch a person as an adult and get caught, you're likely to be charged. Most adults can't defend themselves at all from physical violence, and yet they get to press charges, but a kid who is compelled by law to go to a school he fears cannot? Come on now. Obviously kids will be kids, but there is a huge difference between fighting some kid and systematically torturing him for years at a time.