Same thing with “demons”. Every demon in the bible or any other “true” story is one of many real things depending on what’s being portrayed.

If it’s personal, or non-visible to others, it’s always some mental illness or drugs/poisoning. Whether caused by the environment, a nutter going nuts, or someone getting into something they shouldn’t. Think of how absolutely crazy a bad mushroom trip would be if you didn’t even know what a ‘trip’ was, or that the mushrooms did it. Divine and/or evil work indeed… Many diseases can have similar effects. The easiest example is Syphilis. Someone with tertiary Syphilis going to be freaky and probably act freaky, too. There are many far worse diseases.

If it’s something real, it’s most likely someone being attacked by the former, or similarly an animal the victims were too stupid/uninformed to properly identify. Much like many cryptids can be explained by animals suffering from mange or other diseases.

It has NEVER been actual ghosts/incorporeal beings. It has NEVER been divine punishment. It’s just humans are pretty stupid and imaginative when uninformed.

Rather than try to understand the world, far too many people fall back to dogma and make-believe.