There's a difference between having a preference & stating a (borderline racist, it makes me think of the 'no blacks' signs in b&b's/pubs etc from earlier times) definitive preference on a site visible to anyone. With me, it's a red flag. I'm white, state clearly in your profile no blacks/asians/whatever & you're not the girl for me, to me at least it implies a certain mindset. Just don't reply to people you don't find attractive, don't slate a race publicly.
I can see your point but fortunately/unfortunately not everyone tip toe around the race issue and scream racism at the mere mention of a colour. I only date white women, always have and always will. Every single dating site ask you your preference. I state my preference. Some would not even let you send a message if you don't adhere to all the criteria. I know Match does something along those lines. Or you CAN send the message but there's some sort of issue to get around first.
Perhaps people should stop getting their backs up over trivial issues. People have their preferences, it's not going to change.