Leave what up to the NFL? Collisions on the football field are now illegal? Politically we are in tune but not so much on the football I think. :-}
The league office decides all the time on illegal hits whether they incur a financial penalty or not. The NBA does the same thing. Belichick can submit it to the league office and let them decide. He is just sticking up for his own players like every other coach does. I doubt any action will be taken.