I stopped a kid from hitting me and the school tried to punish me for another kid attacking me, and I non violently grabbed his fist and stopped the attack.

When I learned I'd be punished the same as the attacker, or if I had hit back, I told the school, "Next time, I will knock him out."

I don't recall if the policy was changed, but I was not punished, and no one bullied me when they realized I would defend myself and was prepared to fight back. Don't pick on the quiet fat kid.