FB friend:
The great societal danger of superstitions, cults, and mythologies is not just that they directly harm people, but that they can interfere with a society's ability to discern cause and effect.
People say "what's the harm in people believing what they want to believe", but If the crop yield is bad and people choose to blame witchcraft rather than disease or inadequate irrigation, they're about to do some serious harm.
Moreover, once they've misattributed the cause, the horrible things they do afterward MIGHT ACTUALLY BE LOGICAL. The thing about logic is that it's like a chain: it's only as strong as its weakest link. If you have one terrible non sequitur in your logic, you can employ flawless logic from that point on, but you'll still end up in the wrong place, because of that initial mistake.
Think about it: once you've decided that the famine was caused by witchcraft, it's actually logical to conclude that you must eliminate the witches in order to save the village. Why wouldn't it be? That decision, as insane as it may appear, actually follows logically from the root mistake, ie- your faulty conclusion that the famine was caused by witchcraft.
This is the biggest mistake people make when they think of what it means to be irrational. They think that an irrational person should be irrational all the time. That's not true, and no one could even function that way. Barring actual psychosis, irrational people are perfectly capable of being rational. They can operate cars, invest money wisely, program computers, etc. They just break with logic at critical junctures, usually involving large-scale cause and effect.
We see this in our society every day: people blaming all manner of social or economic problems on scapegoats chosen not after diligent scientific study, but after being roused to anger by a raving demagogue. Or a social media algorithm.