Wow, Films, Art, Culture, Food even, thats a pretty bold statement you've made about America there buddy boy.
*sigh* I suppose I'll just focus on the issue at hand.
Extreme underground music, Black metal is mainstream as fuck (Dimmu Borgir anyone?).
Black Metal (Venom,Emperor) has its roots in Heavy Metal (Black Sabbath, Led Zepplin), which in turn has its roots in Blues Rock(Bob Dylan, BB King), then Jazz, so forth and so on. You think Bob Dylan listens to Emperor, I'm going to step out on a limb and say hell no. Most of those Bands I listed are from Europe and they're all a bastardization of each other.
Music evolves and changes with the times just because a single "American" black metal band wants to challenge the concept of black metal doesn't make them Elitist hipster fags, I mean they very well could be since I don't actually follow the band, Hell I don't really follow any Black Metal Band. However that doesn't mean that just because they suck that every American Black Metal band does. I did do a couple jewtube searches and found that liturgy kinda sounds like every other black metal band with a few exceptions. Now I'm not saying that they're any good. When I'm in the mood for black metal I go straight to Emperor.
I think mostly what I want to say is, Just because you're American doesn't mean that you are an expert on American Culture and that you could speak for everyone of us out there. My Genetic code doesn't tell me to copy/bastardize/reproduce because someone did it better. Thanks.