One of those signs that tell you a business is beyond redemption.
I can only assume that the rare if at all occuring cases where someone in World of Warcraft uses the words "black" or "white" in a racist manner in a name and then someone complaining to a game master is too much work for Blizzard, so they just put those words on the blocklist. (Or blacklist? LOL.) And because they have always been cheapasses, they only use one blanket logic for that, which is a "mature language" filter. Thus, you cannot name your companion pet "white chicken" (despite there being one that already is named that way), because it is considered mature language. Same for "Black Beauty".
So the usual thing happens with such corporate idiocy: It perverts, backfires. Because the implied message in this is that the word "black" is vulgar. And in the context of current politically correct lingo, that's a racist, offensive statement.