by James Ellroy.
I don't know what James Ellroy really thinks of black people or what he's like in real life. Absent other evidence, as readers we should be really wary of assuming anything about authors. On the other hand I think that over time you can and indeed must make some judgments about people based on what they write. It's tricky though. SM Stirling quote:
"And a special acknowledgment to the author of Niven's Law: There is a technical, literary term for those who mistake the opinions and beliefs of characters in a novel for those of the author. The term is 'idiot.'"