I think its a working class music at its very core. Even beyond permeating from the working class roots of Sabbath, a lot of the thrash bands from DRI to Kreator's whose vehemently anti-fascist lyrics are a testament to social change in the 80's. The same can be said for a lot of bands I like Graveland, Mayhem, Darkthrone, Burzum, etc. who reacted against the massive Christian morality of the time. Of course you have a lot of naysayers who said that they were middle-class kids who had nothing to worry about, but this does little to alleviate the alienation these musicians had to Christian society.
I take newer bands a little less seriously now, but some break the mold and employ the tried and true aesthetic mainly the French and Finnish metal scenes that still carry the torch so to speak. Regardless of socioeconomic variables, I think bands from those areas of the world make greating fucking black metal.