Whoever says no just because it is a women, I feel for you. It is as okay as slapping a normal person ONLY when there is a good reason, like being in danger.
You shouldn't just slap someone just to slap someone. That is just evil. Like that women who just got in a taxi and started smashing that guys car and trowing all the papers out, just acting like a little girl on a tantrum. Yes, you can slap her. But not if it isn't in self defense or when she isn't willingly damaging your possessions.
Or that women who beat up a 1 year old of a dad, and nobody wanted to slap her because apparently it is wrong. So that makes hitting a 1 year old in the face full force with fist okay ?!
Basically, it is not normal to slap anybody. You shouldn't unless he or she is breaking the NAP rule. And if people are slapping, there something wrong somewhere in that relationship.