Magister Nemo and Rev. Svengali have both given pieces of the puzzle. But your whole question is hung up in false dichotomies.
It's also worth remembering that, from what I understand of the circumstances surrounding the SB's publication: the Church of Satan
existed before the Satanic Bible did, by a couple of years. An associate recommended LaVey write a Bible on the assumption that it would have a mass audience already waiting for it -- especially people who had been following the activities of the nascent Church already, either because it piqued their curiosity or for more prurient reasons. Basically the Doktor was guaranteed great royalties if he made something that was accessible to the layman, that was salacious, and that defied expectation just enough and in just the right way to make people pass it along. So there was a clear revenue incentive.
Does that mean the book is insincere? Of course not.
Your question assumes that either you exploit people, or you are a sucker. That either you change the world for direct material gain, or you do it for some lame Good Guy reason. Either you know someone deserves kindness, or you treat them as an ingrate. That power means insincerity. That elitism means keeping to yourself.
Above all I think you're failing to see the "third side". This "power" vs. "benevolent" stuff, you have to get over that.
If you think the elitism espoused in the SB is exclusive with a general compassion for the frustrated Everyman, you need to read the book again. (Who do you think the "elite" is, anyway?!) If you think the scope of the Complete Environment is limited to interior design, you need to rethink that. (Can it include your culture?) And if you don't understand the difference between an aristocrat's taking and an artist's giving as different kinds of elitist relationship with the masses, I'd urge you to consider it.
Just a thought. Those who had the honor and privilege of knowing him might correct me if I'm on the wrong track.