it's good info but is it representative of the BM movement?
Well, not really much but again more or less it tells us the summarized version not really as a whole just the movement about metal genres in general, but it gets cooler when the dude reached Norway and did some interviews.The norwegian BM dudes somehow will tell you the why and the how in the vid.
Anyway my 2 cents, Black Sabbath did contribute to the lyrics dealing with mysticism and fear of of *something*,doomish lyrics and etc....with slayer and such,emperor....etc then it gets totally extreme when it gets to Norway
But I guess like FluxUS said "all in the name of rock n roll".......And I think previously it's all about the music and attention but then it has gotten too serious over the years.