Don't get me wrong I believe he was classless ,in fact if female asked me what he did,I would think she was dodgy ,, but if I went around punching everyone in the mouth who ever offended me, I would be in a psycho ward or prison right now. He was acting like a buffoon I think to prove a point, but he said this to that female in a public place, where people were milling around . he was not behaving in a threatening way, rude yes, and I think a 'fukk off' wouldn't go amiss, but I don't believe he deserved a punch in the mouth no.
I have experienced myself guys using very silly chat up lines and getting drinks thrown over them for it,some females behave very badly and it is unladylike to go around punching anyone in the mouth. A lady would have asked for assistance from a security guard or a shop worker, and there were no doubt plenty around if she felt threatened or just ignored him.
And yes if someone spoke like that to my mother or girlfriend I would not be happy at all,but I am not talking about males defending females they care about here,but whether it is right to assault someone when you are offended by them.