"I don't see the appeal of it, so it should be banned!"
I'm surprised BRTD isn't saying heavy metal should be banned.
Obviously banning heavy metal would be quite problematic, but so is the music itself with the frequent promotion of Neo-Nazism and brutal misogyny, and in causing teen suicides.
You're a punk fan right? There is (or at least
was) a very large neo-Nazi punk movement which at its peak was far more influential than National Socialist Black Metal. The National Front (UK) had its own Punk youth organisation. Skrewdriver and other such punk bands fronted the far-right activist movement 'Rock Against Communism'.
My point is we can't condemn entire genres because of a minority of loathesome performers. I don't know jack about metal, but even a casual glance at Wikipedia tells me that National Socialist Black metallists have been condemned by a large amount of Death metallers.