I am so sick of reading about any manner of public figure outside of comedians being called to justice for occasionally behaving like they don't have a stick up their ***. Yet the same media will be the first to lament how dull Belichick press conferences are, as are most Patriots player interviews. Why do you think that is? Any time they try to have a bit of fun (see last year's Welker debacle) the media runs circles around it and asks multiple follow up questions on what was obviously a joke.
Then again, I strongly disagree with the premise that stereotypes are inherently racist. It's all about intent and nature; obviously stereotypes that portray a culture or subculture negatively or as diminishing can understandably be considered offensive. But many stereotypes are just generalizations of attributes and preferences of a given subgroup that aren't really offensive at all, just ignorant and lazy, and have usually served as a B-rate comedian's go-to material (such as an improvising Gronk). I realize and accept that this is not an opinion everyone may share.
The one that's always confused me, and which Gronk used, is why people get offended about generalizing that a certain ethnic group likes a certain type of food. Canadians like maple syrup. Chinese people like fried rice. Are these really things to be getting upset about? I think this is night and day to the Incognito situation; where you have an unquestionably offensive term used in uncertain context there, here is some admittedly low brow humour that is very obviously used in a joking, informal setting that has likely seen more than its fair share of low brow humour.