Eh, it's somewhat conflicting, isn't it?
On the one hand, we're all taught to stand up for ourselves and our loved ones, etc etc.
On the other hand, most of us are taught that violence isn't the answer and you should never resort to violence first.
There's a whole bunch of cultural baggage to look at.
is it emasculating and feminine and proof of the failure of modern society that "we" think hitting a guy for insulting your wife is out of line? Or is it proof we're finally evolving past archaic barbaric hypermasculine tendencies to solve everything with physical violence?
Is it even sensible to say using physical violence is always wrong, when you consider that mental/verbal/emotional abuse can easily be just as hurtful or worse?
Is it hypocritical and sensitive to let a joke from a comedian get to you, when you know the whole point of the Oscar presenters these days is to make fun of the audience? Ricky Gervais said worse things about plenty of celebs.
What changes things a bit - for me - is that Will walked up to Chris and had plenty of time to think. If he'd been standing next to him and it had been an instant reflex, like what? WHAP, that's one thing. But hearing the joke, understanding, thinking, then getting up, walking over to Chris, and punching him 10 seconds later? That should've been plenty of time to think of another way to show your displeasure than just smacking him.
If a customer insulted my wife, and I decked him, I wouldn't get a public discussion about "is it OK to hit the other guy?", I'd get severance papers.
If a kid on the playground hit another kid and afterwards said, yeah but he insulted my mom, he wouldn't get a whole discussion about whether or not it was right - he'd get a note sent to their teacher.
The fact that so many people think the smack was justified, goes to show how much our culture has internalized and accepted violence as normal and acceptable behavior. Frankly, it isn't, and shouldn't be. We're constantly reinforcing in our youth the idea that violence is wrong, except when it's against bad people or people who hurt you - then it's OK. At the same time, we're still trying to further vilify and sexualize nudity, in all contexts everywhere and always.
I'd much rather have a world where we DON'T constantly reinforce those two ideas, but on the contrary inverse them. Nudity is a-okay in most environments and cases, violence is inherently bad and really only a very rare thing. Of course, what that leads to you can see in geopolitics right now - a country willing to smack weaker others around can just do that, and the wiser and more peaceful countries just stand around and watch.