Because the whole "don't hit a woman" ties into the idea that women are the weaker vessel from religion and need taking care of.
If a big dude punches a smaller skinny man, no one bats an eye. Why? Because a man hitting another man is just that.
And no one said "you can either let me hit you or you can get paid the same for the same job".
But if men and women are equal in everything except the idea that a man hitting a woman is bad but a woman can hit a man, then how can you call the equality?
Then your issue is with the fact that hitting a weaker man when you can take care of the situation without doing that is viewed as ok. Again, this has nothing to do with "equality" and the fact that you even make that type of argument makes you no better than those extreme feminists who want men below women aka, they're not fighting for equality..
No, the issue is nothing about the weaker man, read it again with understanding. ---