Black metal mocks the "scariness" of its own appearance and takes itself unseriously to work seriously; Marilyn Manson takes his unserious appearance seriously.
Unlike most music black metal addresses the sublimated void within human experience. A truly dark representation of loneliness, isolation, nihilism, darkness, fear, pain and doubt, once you peel back layers of socialization and entertainment, is the world-view of black metal.
Society hides this darkness, but art has periodically brought it forth coherently, in such stalker-killer classics as _The Catcher in the Rye_ and _In Cold Blood_ or the rigorous minimalist violence of heavy metal. But black metal is the first to approach it with love and acceptance, and through it, to realize that the what society hopes to evade is not the worst scenario it is presupposed to be, and in fact preferrable to the suffocating sterility of a world in which all has been rendered neutral to avoid the potential pain of its loss.
Would black metal have "saved" these people? Probably not physically - the endorsements of violence, fascism, genocide, racism, destruction and sodomy in black metal might have given them new directions to take as well - but in the metaphysical world, yes: black metal would have given them a hope of articulating and overcoming their world, where with another commercial "product" to hear, they had none.
