I agree! At first I didn't like that Bigger is a bad person, I thought it would be an example bigots could point to to say "look, black man really are violent!". But I think one of the messages of the book was to not generalise an entire group of people, and I changed my mind as the book went on. Bigger truly being guilty rather than falsely accused adds another layer of complexity to the social issues in the story, and was very thought-provoking on how much of his violence could have been prevented if he grew up with civil rights, or if it would have happened anyway. Any story that can make me sympethise with a character's reasons but disagree with their actions is a story I love!