I've taken part in some rituals that some people would describe as Satanist and still observe some traditions that you also find in Satanisms creed. I'd no more call myself a "Satanist" because of that than i would describe myself as a "voter" because i vote in elections.
For a start you have to be more specific about what you mean by Satanist - it covers a lot of ground. Mostly these days it refers to Anton LaVeys brand of Satanism which has nothing whatsoever to do with the Christian idea of the devil and mostly concerns itself with pre-christian nature worship.