religion has consistently always been the strongest joining force on the planet. look at what they have done, ruled, created, changed. the point of Satanism is to get that same togetherness but for positive changes like secularism, rejecting the current authority. if you can't see the point, that's fine, you don't have to like or accept it, but the point is obvious. i don't see why it even matters that it is a religion, it's officially a religion to put it on a similar ground as other religions so that changes can be made. a simple club called Satanism is not going to do near as much, it won't have any legal basis, no one will listen or care.
the moment you find any joining force that is 1. more powerful than religion and 2. will be taken seriously, do let me know