These aren’t satanists, properly. They are just God-haters who want to mock. “Satanism” is just their costume.
Service to the Adversary is what it is. If they hate God, they serve Satan. If you call on the Dark in jest, you are still calling on the Dark. “I didn’t really mean it” is not going to be an acceptable defense.
I knew a San Francisco City cop, who had several run ins with that famous Satanist. I won't even mention his name, but he assumed room temperature in 1997. These clowns probably are serving Satan, but they are mostly pikers compared to the REAL Satanists. He said the REAL hard core Satanists don't want any publicity. He said many of the things they do are illegal, so they don't want exposure.