OK...hmm.. Let's see....

That you saw an adult in a position of power attacking a child and the comment you went with was:

"He shouldn't be punching that teenage girl like that, he'll break his hand"

Is probably indicative of something, probably not something good.

Generic anecdote about boxing training is generic, vague and in my anecdotal experience incorrect.

... That should cover it I think

Huh, That was actually easier than I thought.