I agree that the "Never hit a woman," thing is sexist because no one should be hitting anyone, but, to be honest, my reaction to being physically threatened varies depending on the perceived strength of the person. If it's a guy who looks like he could seriously hurt me, all he has to do is act like he's a threat to my physical safety and I'll firmly push him away, trying not to hurt him, of course. For example, if a guy corners me and I have no escape route and he towers over me and stands too close and tries to touch me while speaking menacingly, I'll give him a strong shove and get away. I don't want to hurt anyone, but I want to make it clear that people can't get away with trying to intimidate me like that. If it was a girl who looked strong, I might react the same way. But if the person didn't look very strong, I'd probably be gentler with them, again because my goal would be to defend myself, not to hurt them.