Well, it's pretty darn silly to imagine that unchecked aggression and lack of self control is confined to only one part of somebody's life. His coach is downplaying it because he doesn't want to be called a pussy or similar for reacting negatively to being bodyslammed by a much younger and much larger player who really ought to be showing him respect and deference.

The fact that this behavior is purportedly OK to do to your own coach but not the opposing one is also silly. Patriarchy is stupid. Actual sportsmanship has nothing to do with it. If this sort of behavior has been a part of your world as an athlete, that doesn't mean it's right.