The riot isn't seen in the movie, but it is alluded to. He has this one speech that gives a great sense of texture and paints a picture of what was happening in Harlem then.
“There is sometimes a peculiar confusion in the West that equates progress to whatever is recent or whatever is new, and it is time we understood that progress has nothing to do with the chronology of an idea.”
“I think that in some ways everybody is like Roger. Everybody thinks that when their friends have a problem, that they know the answer and that it's much easier to analyze the problems of other people than your own.”