I think they more see Satan as the lesser of two evils; he's less restrictive, more interesting, and a far more relatable character than Yahweh. Think about it: he gets the hell kicked out of him for encouraging others to question authority, he leads a (failed) uprising against a repressive regime, and spends his time encouraging people to question the "unquestionable." Yahweh's your stodgy, socially and politically backwards grandfather who occasionally lapses into either ranty, holier-than-thou bents, or frightening psychotic episodes. Satan's your cool uncle that you sometimes visit during the summer that makes nachos, barbecues, and lets you listen to whatever music you want, watches R-rated movies with you while you're still technically underage for such things, and lets you play his impressive, oftentimes violent game library. Sure, he smokes and is occasionally a bit weird, but he's everything grandpa isn't...and that is, in a single word, cool.
Satan appeals to the rebellious teenager in all of us. Besides, Christians get to be "actually serious" about their side of the Bible, why can't Satanists? I'm honestly surprised that there aren't more out-and-about Satanists.