Hang on, sorry but I had to read the interview again, because I can't see why you're getting upset at Miller.
He said he got his nickname from robocop & jokingly said that the interviewer was racist because he did not know who Mayhem was in the film because he was a black guy.
The interviewer, who is Puerto Rican, then says i don't mind black people I just don't like Pueto Ricans (or words to the effect).
Again to reinterate what's been said, this was a light-hearted interview & all Miller said, which may be considered racist was he had a PR friend who hated being called Mexican.
Sorry to be blunt, but if this is all it takes to offend you, you're gonna be on a soap-box your entire life.