For two reasons:

(1) Because regardless of whether the standard is fair, in real life, off the playground, violence is as likely as not going to break against my kids as it is to break for them. This "standing up and fighting the bully" mythology is exactly that. The outcomes are simply better if you avoid violence and use the other tools at your disposal.

(2) Because some standards are intrinsically correct, regardless of what the law allows.

Well, I think it's evident that we fundamentally disagree on the action of physical violence. Simply, I believe your views, while commendable are impractical. I know that you perhaps feel mind are barbaric.

Are you Buddhist by any chance? Just curious.

Nope. Catholic. Also, at times an unrepentant vicious asshole. I just think violence is usually not the most pragmatic response.

Well, we'd agree on that then.