Gronk was just making a joke about the guy's crazy dancing. In front of inebriated Patriot fans who paid $87 per head for dinner and entertainment with Gronk. He is an over-the-top, fun loving guy who is capable of outrageous comments. Remember when he was interviewed on stage and said he would f*** Tim Tebow, so he would no longer be able to say he's a virgin. Comedians can say outrageous things for laughs. Gronk is pretty funny and he's harmless.
His other old line was that he was the well behaved tight end on the team and everyone would laugh. (We didn't realize that he was being serious)
Normally not an issue. Traditionally (unfortunately) its been pretty acceptable for Asians to be the brunt of these types of jokes. However, in light of the Jimmy Kimmel mess, this could get more traction than usual. Wait and see.