You say that likely because he loves to act like a hard ass, but he honestly just comes off as the biggest douche nozzle.
he is a hard-ass. It's his way or the high-way and kids that don't like it won't be at Michigan.
It works for him because he wins. If he didn't have great success at making teams better almost overnight everywhere he's ever gone, then it'd be one thing. But he has a track record of winning. Players want to win. Winning cures all ills.
He took a QB that
Kirk Ferentz thought was too robotic and conservative and didn't want and thought couldn't play and he took a bunch of kids that Brady Hoke went 5-7 with and turned it around to 10-3 his first year on the job, and really would've been 11-2 if not for a flat out crazy flukish play to end the MSU game.
I know he rubs a lot of people the wrong way, but I don't know how anyone can doubt him. His track record is proven all the way back to USD to Stanford to 49ers to his first year at Michigan. Everywhere he goes he just wins a lot of games. The man is a hell of a football coach.