In my down time, I did a little reading of their bible. To me it seems like they call it Satanism because you're not believing in a one true god. Or a god in general for that matter. But the belief in ones self. it's more of an atheistic view but with the belief of spirituality and a knack for magic of all the arts, such as Paganism.
I myself don't see a problem with that, nor do i see one in others believing in the devil. I'm not one to judge your beliefs or your reasoning behind it. However I do know that Satanism isn't really just about the devil and sacrificing goats to him.
but more of the fact that you don't believe in god and fate and destiny. and see it as you're the captain of this life vessel. and you chose to do what you want to do. Just like in the garden of Eden, Satan never forced Adam and Eve to eat the apple, but instead gave them the choice, whereas God just plain said NO.
God did force down a lot of commandments, Lucifer gave you the power of option.
Side note: Satanism really is a bad choice in title, in my opinion.
but don't quote me on any of this, my religion is a little shabby. been awhile since i did my religious enlightenment readings.