Firstly, with no free will a medical fact, what ppl say prob has little, if any influence on what they do. Esp, when the statements involve magical beings, powers and beliefs, like a god, deamons, the tooth fairy. Our magical minds ‘say” we believe all sorts of silly stuff – mainly silly stuff. But human behavior is spot-on to the point of there being 7B++. So silly magical beliefs likely have little impact on everyday behavior – or at least it needs to be rigorously and experimentally tested.
The old atheist chestnut that severely mentally ill murderous-sucidal folks are killing for religious reasons, or any reason their poor demented brains self-report, violates the medical facts of the brain > behavior processes. Basically only medical specialists have any idea why behavior happens and that is int infancy of being studied. When people suffering from schizoid brain disorders say the Cat In the Hat made them kill – we never accept that. So, why when the statements relate to some god or superstitious and folklore myth cause killing or harmful behavior?
Where magical/supernatural/religious beliefs seem to cause a problem is when they are reported to drive public policy. But,….here too, we need hard and detailed experimental evidence that magical beliefs utterances, or any utterances for that matter, cause behavior of individuals. Again, probably not.
Personal beliefs, cultural and ideologies seem to have about as much influence on behavior as ethnic food preferences. Best, to presume they are correlated and not causal and test, test, test…