Another thing people making fun of this don’t seem to remember is that she is not only his wife, but she’s the mother of his children. The argument could be made that he was standing up for his family, not just for his wife.
You're Will Smith, and you want to discipline / punish Chris Rock for making an off-colored (or hurtful) joke? A joke with the official sanction of the Academy Awards show?
You take your wife and family and immediately and quietly leave the venue.
Chris Rock would have profusely apologized, but would still never have heard the end of it.
Even better that Will Smith would then not have been present to pick up his award!
Regards,