I heartily disagree. The number symbolizes the antichrist, destruction of God's creation, and hell on Earth. Not exactly nature loving peacenik from what I can tell. Also a Satanist and atheist are two completely different belief systems.
I don't want to drag this out, but one quick note: The two most prominent Satanic organizations in the US, LaVey's "Church of Satan" and the Detroit-based "Satanic Temple", are both explicitly atheistic. They seem to view Satan, along the lines Castleview suggested, as something more like a symbol of self-realization, enlightenment, etc. It's all pretty silly to me (I'm no great fan of prodigal metaphysics or even pseudospiritual theater), but the latter organization has at least done some tangible good in calling attention to breaches in the Establishment Clause that other religious institutions have been permitted to get away with. None of this, of course, obligates you to buy anyone's music, but the detail is worth mentioning.