They don't capitalize Confederate, they don't capitalize white when referring to race, but they do black... Do they think the rules of grammar grant some kind of social prestige? Satan is capitalized, Nazi is capitalized, it helps us determine we're talking about a proper noun, something distinct and specific. It makes reading easier, especially for foreigners. If it's capitalized, you can suss out what kind of word it is compared to other nouns in the sentence.