The Church of Satan always comes off as a joke that went to far.
Bob Larson and a few others have tried to build this notion that there are Satanists in every city plotting evil things. It's a very exciting notion to a lot of people which is why Bob Larson was so popular. As it turns out, there are very very few people that call themselves Satanists and they are not really very interesting.
The real dangers to Christianity are fruitlessness that comes from "The cares of this world, the deceitfulness of riches and the desire for other things".