Here's a video by Simon Winchester about Al Jolson that's very pertinent to this discussion:
https://www.youtube.com/watch?v=f5Tm7bMUhUw
It seems Jolson is thought of as a racist today because he's mostly remembered for the film "The Jazz Singer" in which he appeared a lot in blackface. In fact, he was very much not a racist in real life and helped a lot of black performers get their start. Newspapers in Harlem proclaimed him a hero and huge numbers of blacks attended his funeral.
It's hard to judge another time from our time. And given the issues we face today I'm not sure our time is so much better than the past.
Barry