The "why didn't the player hit him back" people are Fake Sugar Dick (WARNING, NOT THE REAL SUGAR DICK!).
"Why didn't the player hit him back" is the wrong way to look at it. How didn't anyone is a better question. You act like someone getting their nose broken has to be some kind of premeditated act. If someone threw a ball at me and called me a rough ridin' man of taste and distinction its hard for me to imagine that I wouldn't lose my temper.
In some aspects, they have more to lose than their coach. If an 18 y/o strikes back at a coach, that follows him forever. That kid will always be known as the player who hit a coach. He'll be labeled as uncoachable. It could ruin his career.
A coach puts his kids through hell until one day some kid snaps, and he'll spin it as a wild young kid with an attitude problem. He'll get a second chance.