Not punish the kid hitting back at someone who was bullying him?
Not punish the kid who beat up the bully?
It actually helps to have some idea of what's going on in the school yard, ask witnesses what was going on, and IF KIDS COMPLAIN ABOUT BULLYING DON'T TELL THEM TO GET OVER IT. "You're not making an effort to fit in" is blaming the victim. I'm not making the fucking effort to fit in because the other kids treat me like dirt. Why should I bother to try fitting in?
But yes, the adults could have looked at the situation and realised that the bully was getting their just deserts. Punishing the victim who has been pushed past the end of their tether is not helping anyone.