I think it's what happens when privileged people try to write about the real world. You get "blacks" and (my favourite) "poor" people. Then there is everyone else. Shouldn't it just be that there are "people", and some of them are high income, and some are low income?

I have met lots of different types of people through my (very middle class) life and the ones who seriously use "blacks" or "poor" to describe groups of people are usually the very cushioned, over-educated types who are totally clueless about other people's lives.