That's the rule, right?
He was head hunting. So was Marshall. In my opinion, Marshall's hit was even worse after seeing it again. Way late and clearly illegal. He watched Newton throw the ball then went in for the kill shot.
They both launched and led with the helmet.
Now the second one in the video below is a crowded pocket so that one can be labeled incidental.
If you look at the other two both players launched themselves and led with their helmet aiming at Newton's head. They weren't trying to make a tackle or even lay a hard hit, look at their arms.
It's pretty obvious they were headhunting to me. Again I'm no fan of Newton, but that crap last night should get fined, and frankly if I was Goodell I'd call the HC and DC and have a little talk with them.
Take a look: