It's literally brainwashing techniques: if you repeat something often enough from an "authoritative" source then the information bypasses logical skepticism and many (more than half) of people just accept it as truthful.
It's a great adaptation for energy savings actually - e.g. engineers MUST use this principle on a daily basis when working in a team environment, or else nothing would ever get done. Even scientists whose literal job is to question EVERYTHING don't re-examine every single precept every single time (is this water that I am adding now? okay now, I am moving my right hand, but is it really MY hand, in the grand scheme of things?:-P oh no, the thing I just picked up, a second ago, is it still the same thing now?).
i.e. active disinformation is extremely destructive, and most people today seem to have few defenses against it. Especially when religion is co-opted as the delivery mechanism.
Thing is, not all these people have less than two braincells to rub together. It's like flat earther's. Not all of them are stupid people. Maybe just never got taught critical thinking until they'd already been indoctrinated in some religion (evangelical Christianity usually, but not always.) Or grew up before the internet, and so fell into the echo chamber trap. Or their parents only watch Faux News and so that's what they watch.
Calling all these people stupid isn't really fair. I know stupid people who think all that shit is ridiculous.
No, it is exceptionally fair. Is someone who could do better but chooses not to also being stupid?
This is mortality. One mistake can cost you a leg or a life in something as common as an auto accident. Why do you want to make excuses for people who are choosing to make it worse?