Forest was probably the earliest post-war civil rights advocate. Do a quick search for his speech to the Pole Bearers. It can bring one to tears.
I've read some of the things he had said on the subject. As the founder of the KKK, people think he was a horrible racist evil man, but in fact if you look at what he actually said, he comes across as a very decent man. He had no desire to do the things that the KKK later were known for doing, and he expressed regret that it turned into what it became.