Is it always a bad thing?

This is a very difficult subject. Something I always had a problem with is that it is socially acceptable for a woman to slap a man but if the man did the same thing then it isn't socially acceptable.

Naturally violence of all sorts is bad, and I don't plan to hit anybody at any time, but why is it so black and white that hitting a female is a heinous offense?

I like to hear your thoughts.

Thanks.