As others have said, what lessons are there for the players if the schools are fined, but no financial implications to coaches or players? Coaches either 'coach it or allow it' with on field personal fouls and unsportsmanlike behavior, why not the same with unsportsmanlike behavior post-game?
Why not treat it like targeting for penalizing the players? Sit 'em for the next game. Hockey does something like that by kicking out players for certain majors, and that threat hanging over the players has minimized outright cheap shots, and all but eliminated fighting.
Fine the HC whenever it happens, fine other coaches/staff who aid and abet, fine the players involved, fine the AD, fine the school, take away bowl or media money, suspend the players and coaches. Taking away individuals' money and playing/coaching time will have an impact. If coaches and players can't figure out good sportsmanship on their own, give them some incentive to do so. Let's make sure sportsmanship and character always matter in college sports.