When I first heard that Mad Dog said it, I immediately was reminded of the President of the PGA, Ted Bishop, WHO WAS FIRED for tweeting that Ian Poulter was squealing like a little school girl during recess. End of his job just like that because he broke a political correctness rule.
But there is a lot of distance between what Ted Bishop did and Mattis. I don't think this is going to gain traction.
I care less about who the secdef calls a pussy than the fact he can call someone a pussy and not lose his job. More winning!