Why? It's no different than how blacks use the word "blacks".
some people (Blackace, for one) draw a strong distinction between "blacks" and "Blacks." I prefer the lowercase if only because "Blacks" reeks too strongly of a trademarked brand name
I've always been opposed to African-American (or Anything-American) due to how imprecise and assumptive it is. It's extra silly once you start looking at other countries, for example the UK. Oh, so now
Paterson Joseph is an "African-American"?
in conclusion, I wish I could wear my All Blacks jersey in Los Angeles without getting beat up