What about descriptive words for people that aren't race-based? Pedro and I have been having this discussion because he doesn't get why the word "hermaphrodite" has been replaced by "intersexed."
I tried to explain that it's like the difference between "midget" and "dwarf," but he didn't get that, either.
There are lots of these, though -- homosexual vs. gay, retarded vs. mentally challenged, fascist vs. Republican*...the words we use change over time because our attitudes towards people who are different also change.
Back when people with Down syndrome were taken away from their parents and institutionalized for life, we called them retards. When we started realizing that what they need is extra help and accommodation, we changed BOTH the way we treat them AND the words we use to describe them.
The same is true for people with autism. Kids with autism used to be labeled "retarded" and locked up too. When autism became an official diagnosis in 1980, we started treating autistic kids differently because we started viewing them as a separate and unique category. There is still debate among parents of autistic children about phraseology -- I've heard the following permutations used with utmost seriousness:
My son has autism.
My son is autistic.
My son is an autistic.
My son is an autist.
My son has special needs.
Yes, that's right -- some parents refuse to use the word "autistic" in front of their autistic kids. Like it's a dark secret. My brother and his wife are in this camp, and they're now struggling with deciding when to tell my nephew -- he's eight -- about his diagnosis.
We're of the "tell 'em early, tell em' often" school of thought. Reminds me of what Cort has said before when asked when his parents told him he was adopted: "When did yours tell you you weren't?" Putting it off attaches a stigma to the word that is impossible to mitigate. If there weren't something wrong with being that way, why wouldn't you want him to know about it? [/autism denial rant]
Anyway, the point here is, I think changes in language reflect changes in attitude, and I think the debate is less about what the groups being described want to be called (we could, after all, just ask the individuals we associate with which they prefer) and more about "outsiders" being unsure how to relate to groups of which they are not members.
Personally, I go with "black" because "African-American" isn't correct in many cases. Colin Powell and my black sister-in-law are both Jamaican-American. (Technically, my SIL is part African-American and part Afro-Jamaican, and her kids will be Afro-Jamaican-Euro-Hispanic.) So unless I know someone's actual heritage, I tend to go with the word that describes their outstanding physical characteristics (whether that's dark skin or red hair) than to make assumptions about when her family arrived and from where.
*just joking, guys.