When I was in highschool, I saw a friend of mine getting pounded by a kid bigger and older, but did I try to be an asswipe hero? No, I rushed over, pulled the guy off of my buddy and tried to talk about it and calm the situation.
Even then I only got involved because the victim was a friend of mine. Men who see a man just roughly handling a woman and cheapshot the guy without knowing all the details of the situation are mangina scum.
Now if a guy has the woman on the floor and is really pounding her face in, then I can understand using extreme force because that might be necessary to save her life. But there are a lot of guys who will just cheapshot a guy who they just see smacking a girl around without even getting his side of the story because "men shouldn't hit women". All men like that need to be systematically exterminated.