Not only that, but the years of trauma she's put him through by emasculating and cucking him
That is the primary point, right there.
The slap wasn't about a hair joke. Nobody thinks less of Mrs Smith's beauty due to her haircut. Dolly Parton and Cher (among many others) have never been seen without a wig in many decades and none of their fans think any less of them because of it.
What Rock got slapped for was the result of Mr Smith getting publicly cucked and humiliated and dragged for months on end. Not just with the "entanglements" guy but also because she's made it clear in front of the studio audience that she's always loved Tupac more than him.
It can be argued that Chris Rock crossed the line by "bald-shaming" a woman who has made videos about her condition, but I think we can all agree he took that slap like a guy. And (so far) he's proceeding exactly how we would expect a guy to proceed having taken the risk and getting called on it. Sniveling about it or pressing charges would only make things worse for him. As it stands now he'll have no trouble weaving this incident into his stand-up and his fans are going to love him for it.
Mr Smith will come out of this just fine, too. There are plenty of feminists who will support him being the ally to the strong and independent woman; and there are plenty of trad-cons who will support him for doing his duty to his wife, her efforts to actively emasculate him notwithstanding. His next action flick is going to get plenty of fans. If it's any good. And none of them are going to care that he basically stole on Chris Rock with the slap for running his mouth.
But Mrs Smith might not come out of this so easily. If she had simply stood up and said her piece from the front row Rock would have offered the profuse apology right in that moment. She'd have handled it like a boss. But she didn't handle it on her own. She allowed her man to go do it for her.
Not brave. Not stunning. Not fierce. And not independent. That might end up leaving a mark.