Firstly, as I assume that you already know, that Satanists do NOT worship Satan. They look to him for inspiration. They figure that this being was in the highest ranks of God's Order and decided to leave, i.e., kicked the hell out! LOL
They praise Satan for following his own path and that they should do the same.
Their motto is "Do What Thou Wilt". Think of anything and if you want to do it, then do it. Horse dating? Approved! Beheading the first person you see in the morning? Approved. If you want a husband or wife in the 3rd grade? Approved!
Satanists worship themselves and all the desires that they can fulfill in this life and in their minds they feel like that is OK.
If you think you're going to be neutral in this spiritual war, you got another think coming. The choice that you think you are making has already been made for you.
There is some validity to their motto. You paint it in a negative light and of course, it could be taken into a negative direction but it's unlikely that one could build an army to genocide entire races of people because those people won't do what they want to do.
Christians and Satanists are really just 2 sides of the same coin to an extent. Both will claim to hold the right way to live and that's the problem with both. Neither knowingly worships God in this mode but both do.
Service to self is ultimately service to God because the Self is God. Simultaneously, service to the other is also service to God because the other self is also God. Herein lies the fault of each, they both serve God but they do not see him in themselves or the other.
The difference is suffering. The Satanists way causes suffering to self because the pursuit of desires only leads to suffering because they can never be obtained to satisfaction. You never actually get what you're chasing because the desire only reinvents itself. Ironically though, the Christian way is the easiest way to cause the most suffering because it appears infallible. The safest place for the devil (the ego) to hide is in the church. You tend to cause suffering by judging yourself and others for not properly upholding the "rules".
Truth is, nobody's doing anything "wrong". Everybody's worshiping God.
I hope you don't think that I could read the Mind of God, but if you ask a certain person on this board that say that they are God, you would get an answer. LOL Just kidding.
My ego hopes you're talking about me, lol. Because I did say I am God, but I also said Jesus is God and you are God and so is everybody else. If all of us knew we were God and could access the entirety of the mind of God (us), there would be no point to this entire experience of life. In fact, there would be no experience at all because there would be nowhere to go, no one to meet and nothing to do. God would not be able to perceive or interact with anything other than God. Of course, that is actually what we're doing anyway but we are largely unconscious of it so as to have an experience of something.