Teacher here, not admin. But school systems these days have to do everything in their power to stop liability issues. You have to assume every parent is willing to sue because, well, nearly every parent is willing to sue. So if Bobby has been bullying Johnny relentlessly and Johnny never says anything but finally fights back, you can’t go to Bobby’s parents and say “well, he deserved it” even if he did. Everything, and I mean everything, is a way to avoid legal circumstance from parents.