Satanism isn’t a real religion. It’s a mockery of religion. Reject the fools.
Other fad faiths began as satires too. E.g. Scientology.
IMHO, these folks are mere dabblers. Other than the devil symbolism they don’t really go very far beyond vanilla secular humanism. If they addressed the devil in earnest they would probably soon be freaked out.
Just like Atheism, who I have found along with Satanist run in the same crowds..