I dislike phrases that single out a gender or sex and apply a common sense standard, because it gives the impression (to some) that breaking that rule is less condemnable when done to the other group. Logically that's not the case, but humans are not logical.
So it should be "you should not hit anyone": you don't hit men, you don't hit women, however when you're attacked you're not dealing with a man/woman anymore, you're dealing with a beast, and self-defense is justified.
So to answer your question, if Roberto had puched her when she was attacking him, it would have been justified. He did not, and did not escalate the situation, which is good, however the sentence he said "I'm a man, I can't hit a female" is misguided chivalry. Again, if you are a gentleman, or if you are lady, you don't hit people, if they attack you, that ceases to apply.
First, she's not a beast; she's a woman; a person. Lol at repeatedly calling a person a beast then complaining about the ethics of someone regarding a person as a person (subcategory: woman)) as a bad thing, or suggesting more violence would be warranted. Holding back is an indicator of civility, the opposite of beast behavior.
Second, chivalry is about, among other things, both rules of fighting/ engagement generally, and also particular respect by men for women.
Sure, she wasn't acting like a lady (or emulating gentlemanly behavior, either, obviously; she was retarded, entitled, violent, and (understatement: ) disproportionate...and criminal but the point of ethics is having principles and applying them. A man who forbears from hitting a woman because she is a woman when he or others are not in ongoing danger is not misguided; he's following a personal code of ethics with a larger paradigm than the immediate moment. And 99/100+ that will be the better choice. Odd to suggest he should change his ethic to go toward greater violence.
Other option is that that was a face-saving statement for being afraid, or for not having an immediate reaction to throw down with a larger person who is already physical and in a tizzy/potentially crazy. Or for simply not having a personality that throws punches or gets in scraps, regardless of situation. I prefer to think he simply made an ethical decision, but not hitting her is OK in any of those cases.
And as you note, practically speaking, his choice not to engage was (also) a wise one. Hitting her would have served zero purpose. He wasn't in further danger, and it was about a bowl of food. Any criticism of him for not hitting someone when it wasn't necessary to, or for having some blanket ethical rule for himself is dumb, especially when the outcome was what it was; he obviously made the correct choice on multiple levels. Not in danger, and not his job to fight to protect the company's assets.
Personally, I hope it was for chivalry's sake, because it worked out, and ethics and decency should work out more often.
On the broader point, I'm not threatened or bothered by a little artifice or somecrespect-based rules that align to sex that 99/100 have a good outcome. Exceptions will happen. But taking into account the overall relative directions of both volume and severity of violence occurring between individual men and women, a chivalrous element to ethics is the last of our worries.
