I'd say you were wrong on a couple levels, why would you even be in such a conversation? I don't have the context to decide if it was whitesplaining or just ordinary racist. If it is someone you know, contact them and try to salvage the relationship. If it's a random, anonymous person on the Internet, just count your losses and try not to repeat the behavior. Classifying any group of people as anything is wrong, Black women calling themselves or others "Queens" is most likely either a term of endearment or self-pride not often bestowed by others. You were probably a bit misognist as well.