@xianc78 These are all sponsored by a small organization that targets schools with religious clubs. They don't actually want to run Satan clubs. Their goal is to get the religious groups cancelled. The schools can't allow a Christian club and exclude a satan club, because that would be religious discrimination. So the schools cancel both. The better response is to "welcome" the Satan club, but rally the community around the Christian club, which is what is actually being attacked. These groups will fuck off when they realize they aren't getting the response they want. They have no interest in actually running clubs.

@xianc78 If it's Laveyan Satanism (IE: basically just Atheism with some edgy theatrics), then I don't particularly care.
As others have said, it's mainly just a way to one-up Christian clubs and the like; and the only kids who would join it are probobly going to be reject goth/metal heads who are doing it because *edgy* or to piss off their parents, and will probobly find the sense of community positive.
They'll play pretended for a bit, listen to some Marilyn Manson together on the weekends, flash forward a few years and it's all a goofy memory they share.