This is easily argument is easily simplified:
A christian can't listen to black metal because the lyrics are satanic.
To listen to the music is to support the lyrics.
If you listen to black metal you are therefor a satanist.
or
anyone can listen to what they want to
From what i'm led to believe, the satanic overtones in the black metal culture weren't really ever (or maybe originally) about being a satanist. In norway christianity overtook that countries traditional beliefs and gods etc. Those in the black metal scene didn't like it and wanted to follow the old ways. Making satanic music was a way they voiced their opinion. The church burning was a further display of that contempt with christianity. So basically, what i'm getting at is that it wasn't really making music about their worship of a deity as much as just rebeling against something they despised for another reason.
I hate religious debates.