> A key smell test is: Does receiving pushback or counter evidence strengthen your conviction that you are correct?

The parallels with religion are obvious here too. I would guess that the fall or organized religion participation in America directly matches the rise in political zealotry and/or conspiracy theory belief. There’s always something people believe more strongly the more it is opposed.

To be honest, while there are definitely religious fundamentalists or literalists who suffer from this kind of thinking, I don't find it to be any less prevalent among people who identify as atheists or rationalists. It's a problem of rigid thinking, overcommitment to ideology, and being unwilling to question and overturn your premises. If you are willing to hold beliefs lightly, entertain ideas even if you do not accept them, and remain open to new evidence and to changing your mind, you're probably on the right track regardless of other factors.

A lot of religions teach that reality and God's will is mysterious and open to interpretation. That can be the cornerstone of an epistemic humility, if you cultivate it that way. (I'm agnostic for what it's worth.)