So is black metal music racist? Give me a break, people have associated black with evil things such as monsters stalking the night, plague, and death for 3000 years and probably before it. You are paranoid and overreacting. You're projecting your own racial insecurities onto the world where there simply is none, especially in this case.
I didn't suggest any of this was racist. I despise the hysterical, wolf-crying, race-baiting PC police, but that doesn't mean that we can't try to make the word a better place by avoiding to pile on the black=evil association in our culture and in the English language, especially when coining new terms. It's not a horrible moral failing not to do so, but it would be nice.
Metal is not a person, but a nurse is. All the difference. My point isn't to suggest it's racist, but to ask why even go there? If they changed the term slightly no one would have to double think.