I had to get up and walk around then come back to figure out why this post bugs me so much but like… is it a problem for you if people believe in things you don't? They believe in gods and angels too...? Is that also a cause for panic?
IF we rule out everyone who believes in things that are not Science as mentally ill, foolish, inferior, or "mass hysteria" then you have cut out everyone but some of the most insufferable Atheists, the really obnoxious ones on reddit.
I personally find the level of panic people get driven into by their ideas about how prevalent this kind of thing is and how it supposedly affects tactile life, all of that more concerning than their belief in it.
But like, ...Yes some people DO believe in gods, demons, magic, MagICK, devils, angels, shifting, therianthropy, afterlives, spirits, animism, beings of powers, and a lot of other stuff. What is that mattering to you? And how is it surprising?
If you had specified you mean Evangelist USA Christians, and if we assume that is the original intent here, then YES: The concern I have is for the FEAR these people live under, NOT that they believe a devil is real ( i happen to as well) but that they believe they are in such horrific daily peril from him as to sound like they all have serious PTSD from perceived Dangers AT ALL TIMES. Like… guys. yikes. Does God not watch over His own? THAT is concerning.
But to understand them you have to know this is the fear they are in all the time and they really do think their souls are in danger from watching a miyazaki film or being tempted into wearing a crystal.
My people, in our tribe, also believe one of our great elders turned into a big stone and he's there to this day and that back in the old days some of us could turn into bears at will. I'd like to hope you don't think we're having mass hysteria.