I spent a good deal of my youth thinking that there was a true connection between goodness and good music, and I have spent a good deal of my adult life finding that there is really no connection at all. Granted, there are and there have been great performers and composers who have been highly moral people, and there have been lousy composers and lousy performers who have been highly immoral people. I have played great performances with people who I would disagree with wholeheartedly on a number of issues, both personal and political, and I have played disconnected performances with people who I admire a great deal as thinking, feeling human beings.
The best-known case of a great composer who was a horrible person is Wagner. As much as I despise what I know of him as a human being, I am a sucker for his music. Wagner shared his vocal opinon of Jews, particularly Jews who were composers, with Vincent D'indy. D'indy's music isn't played all that often, and I imagine that the majority of 21st-century music lovers who know his work at all only know his Symphony on a French Mountain Air, so it would be easy to dismiss him as a kind of "one hit wonder." He was as antisemitic as Wagner. He even wrote a blatantly antisemitic opera, and claimed that Jews were not capable of creativity. He was also rather fascist in his thinking, but I have read that he was not completely out of step with his early late 19th-century French anti-Dreyfus contemporaries, many of whom were not accomplished composers.
I would love to hate D'indy's music, but I can't. His instrumental music (I haven't heard the opera) is stunning. His orchestration is brilliant. His ideas are fresh. He writes beautifully for winds, strings, and brass, and piano, and he often uses really interesting combinations of instruments in his chamber music.