Yes, the performance was... was.... peculiar.
In addition to the various possibilities already expressed in this thread, let me offer another one.
Back before there were cameras and recorders and microphones everywhere, we as a society tolerated... maybe even embraced... what I call "Ethnic Humor". We told jokes where the people of Polish ancestory were assumed to have some kind of unusual mentality. In the South, many Baptist preachers often included anecdotes in their sermons which began: "Did you hear about the Colored Preacher who.... ". In Indiana we used to tell "Kentuckian jokes".
Call it dignity, call it being courteous, call it political correctness... we shy away from that these days.... at least in public.
Certainly Democrats have speech patterns at times that could use some clean up, but my observation is that withing Republican/Conservative circles, particularly in meetings where the general public is almost non existent, there is a style of humor that I think of as "snarky" that is very much in vogue. I suspect Clint Eastwood is surrounded so much of the time by people who agree with his political views and people who never push back with a "that might be a bit abrasive for public meetings, Clint" that if someone today tried to explain to him that he was a bit too edgy last night... he might have trouble understanding what they were talking about.
O.K. At the next meeting of our club, we will discuss the edgy comments of Joe Biden. ;D
While I certainly do not agree with the first part of your post, and would agree that the comments that Biden has made over the years be discussed. It always amazes me that when a conservative "offends" someone the whole liberal establishment gets up in arms but when "Old Joe" makes a stupid comment it is just shrugged off as " well that is old Joe". The double standard in this area is sickening.