Is it not up to the viewer to decide what is tasteless and what is not? What is offensive and what is not? Jimmy Carr doesn't offend me in any way... nor does he offend the vast majority of his audience because they know that a part of his show is heckle and response. It's not like Chris hasn't riffed on Will Smith in the past...
Will seems to not have a problem with other people "being" with his wife since they're in an open relationship... what does he care about this joke and Chris Rock speaking his wife's name? I'm not judging their relationship, I'm just stating what is apparently well known.
Celebs know they're going to be roasted a bit at these ceremonies... and I guarantee you that joke was signed off on by the Oscar Committee. Watching it again, Chris was in a rhythm when he got to that joke... if it was off the cuff or an adlib I'd assume that his rhythm would have been thrown off a bit. Whether he wrote it or not (seems like I remember reading somewhere that comedians, other than those presenting, write jokes for these ceremonies), it sure seemed to be part of the script for the night. As far as roasting goes, that was an lightweight joke for certain.
All this talk of Will defending Jada and his family... how would our discussions change if Chris had decided to defend himself in the same manner? Does he not have that "right"? What if Chris had decided to defend himself? I have to say personally, that I would have a hard time being physically assaulted by another man and not responding in-kind... Chris is the better man in this instance. But what if Chris wasn't the better man? How would this conversation change (not here specifically, but in general)?