The consensus that men should not hit women is made from the thought that men are stronger than women. This belief has been supported by mumbling things such as testosterone and bigger hearts. While this may be true, a natural advantage does not automatically translate into an actual advantage.
Due to the separation of gender roles in earlier society, women were not generally given opportunities to show they can be as strong or stronger than men. The situation is different now and the Olympics even has a women’s weight lifting competition.
Another contributing factor is the belief that women must protect themselves from men. This facilitated the creation of self-defense classes that revolve around teaching women how to incapacitate a man.
The rule that men should not hit women was made out of fear of women’s safety.
I don’t fear women’s safety. I fear my safety.
I am not in a position where I am at all threatening to anybody. Because of my weak, small and under-developed stature, I am in a similar position women may have been in long ago. Therefore I hit women, not because I am a sexist man but because I am well aware they can beat me up. The roles have been reversed. There is no longer a fear I can beat them up. That loss thus eliminates the reason behind the rule such as they apply to me.
My lack of strength is so great that it carries this argument to include small children and cripples.
I live in constant fear of being assaulted by women, small children and cripples.