Milwaukee Journal Sentinel opinion:
"Q. Why does the Journal Sentinel capitalize Hispanics, Asians, Latinos and Jews, but not blacks?
A. Our practice is to capitalize ethnicities and nationalities, not racial designations based on a skin color, such as black, white, brown, yellow or red. Some ethnicities generally denote race, such as African-American or Asian, and yet, there are Africans who are not black and there are Asians who are Caucasian, even if their skin is brown. Someone who is Hispanic can be of any race.
The only races generally described in terms of color are black and white, and to capitalize either or both would be jarring to readers because neither word is a proper noun.
Most newspapers now consider African-American and black to be interchangeable, except, of course, when it wouldn't be accurate. If a source prefers to be called one or the other, we honor the source's preference. Our style is to generally use American Indian, but if a source prefers Native American, we will use that. "
In your sentence it is used as a proper noun. I guess.
