Interesting POV. I never used to watch Archie Bunker as a kid, because I never understood the appeal of the show. But the joke you reference is like a layer cake of takedowns on American prejudice:

Archie thinks he’s accomodating the different “colored” culture that he sees in the Jeffersons. When confronted, he says that “that’s the way Al Jolson always talked,” who was of course a white man in blackface. So he complies with Mrs. Jefferson’s request, and she’s so pissed she’s already decided that she’s done with him. Then George speaks up in defense of segregation.

I love the gag.

Mind you, this was already a pretty tolerant situation, for 1973. George Jefferson and his family are hanging out with the ultimate Queens bigot, Archie Bunker. How many White folks in 2019 are inviting Black folks over for drinks?

Norman Lear was a genius.