And well, Enel was attacked too. Not by Robin, but by Wiper (and they acted as a group there). Sorry, but this is what you get when you bitch with someone miles ahead of you.
And as to defending yourself...Zoro didn't need to squeeze the shit out of Miss Monday like that. It is exactly the same situation - 2 extremely one-sided "clashes" against women. It is just funny that a line like "she is a woman" comes from someone like Zoro, who had absolutely no problem doing this:
I mean come on, if you look closer you can even see Zoro's handprint on her face. How disturbingly violent is this please, getting your head squeezed till foam comes out of your mouth?
But look where Zoro had mercy and only used the back of his swords to "defend himself":
A kid and a good looking (at least normal looking) female.