There were two concerns, as I understand it: there were (and are) Christian groups that believe that "dark rituals" can have real and serious consequences for not only the participants but the society that allows them to occur, whether that's literally summoning the devil or, more commonly, just provoking divine disfavor (the kind of people that blame various disasters on divine disfavor due to tolerance for abortion, gay rights, etc.) But there were also concerns that satanic cults, whatever activity they started with, progressed to ritual violence including sex crimes, assaults and murders, and suicides. Overtly, the government and law enforcement involvement in the satanic panic was driven by the latter type of concern, though a lot of the propaganda that fed that concern was spread by people who were also involved with the more.religious concern -- they weren't independent phenomena.

It still baffles me as an adult that actual adults can believe that stuff.

Edit: I'll add I don't go around telling people how silly I think they are for believing these things, but it makes as much sense to me as telling me aliens live in our shoes and if we don't tap then three times before taking then off they will harm us.

The Satanic Panic most prominently involved railroading childcare workers on the theory that they were sexually/satanically molesting the children. The threat model there is fairly easy to understand.

People say we've come to our senses, but the unreasoning panic about anything that might be related to pedophilia is actually still very much with us.