There's nothing natural about running full speed into a guy that's running full speed at you. I guess this puts me in the "man's game" crowd. I understand your point, but how is that any different than a power running back completely ducking his head and shoulders to gain a yard on 3rd and 1? Should they be penalized?
The league is treading a tight rope trying to prevent these injuries. To go so far as to throw the guy out of the league (especially for that hit last night) would be outrageous. I would hardly consider it a dirty hit.
Harrison is a strong, physical player. He hit a weak, frail quarterback, at full speed, while the QB was stopping to throw the ball. It's gonna look bad. It's not like Harrison launched his helmet into McCoy's; he puts his forearms up, and unloads all his strength into the hit. The result is he hit McCoy in the face, so flag him. That's the rule. It was hardly dirty, though.
For anyone who missed it, here's the video:
http://www.youtube.com/watch?feature=player_embedded&v=YDvi5vGsY90