Why? For the same reason that some head coaches would like to punch him--he wins wherever he goes regardless of the situation.
His reaction is priceless and about what fans and his players would expect:
I get why other coached would want to fight him. Meyer went into an impossible situation last season coaching a team that was being sanctioned thanks to Jim Tressell, Terrelle Pryor, and the rest of the tattoo gang.
His players knew they had nothing to play for but pride, and while you would think that would be enough for a lot of players it is not. They want the glory that comes with the conference championship and the thrill that comes with a big time bowl game. Knowing that they can go undefeated (like they did) and be stuck at home takes the wind out of your sails before the season even gets started.
In comes Urban Meyer. He steps into what would have been an impossible (or at least a really difficult) situation and guides the team to an undefeated season. Not only were they undefeated, but had they been eligible there were many that thought they deserved to be in the BCS Championship game over Notre Dame.
Not too may coaches can pull that off, and that has to be frustrating to those that can't; so frustrating it might even make them lash out.
But that's okay. Because what happens in Fight Club stays in Fight Club.