I keep thinking about the first Avengers movie, when Loki is standing above everyone going "See, is this not your natural state?". There's some perverse security in not getting a choice, and these rationalist frameworks, based in logic, can lead in all kinds of crazy arbitrary directions - powered by nothing more than a refusal to suffer any kind of ambiguity.
I think it is more simple in that we love tribalism. A long time ago being part of a tribe had such huge benefits over going it alone that it was always worth any tradeoffs. We have a much better ability to go it alone now but we still love to belong to a group. Too often we pick a group based on a single shared belief and don't recognize all the baggage that comes along. Life is also too complicated today. It is difficult for someone to be knowledgeable in one topic let alone the 1000s that make up our society.
I agree with the religion comparison (the "rational" conclusions of rationalism tend towards millenarianism with a scifi flavour), but the people going furthest down that rabbit hole often aren't doing what they please: on the contrary they're spending disproportionate amounts of time worrying about armageddon and optimising for stuff other people simply don't care about, or in the case of the explicit cults being actively exploited. Seems like the typical in-too-deep rationalist gets seduced by the idea that others who scoff at their choices just aren't as smart and rational as them, as part of a package deal which treats everything from their scifi interests to their on-the-spectrum approach to analysing every interaction from first principles as great insights...
