>>125244303There is the risk of escalation.
Maybe the bully quits, or maybe he's unhinged and the next time the bully wants to harass you to recover face he brings a knife. Or worse.
And if you survive that instead of getting sneak attacked then YOU will be carrying a knife to defend yourself.
And then the meta is kids in school are prison fighting with shanks and knives and having good old school gangwars, so everyone has just lost even if it was obvious who the bad guy was.
So the safe option is that kids just shouldn't fight. Even if it's fighting fighting back.