Jargon-filled summary: Pursuing the epistemic-clarity ideals of the rationalist community can sometimes be instrumentally harmful at the beginning of the journey, because the aspiring rationalist may take seriously the literal (and therefore incorrect) interpretation of cached beliefs that they formed in the past for hard-to-analyze instrumental-mode reasons.
Within the Christian tradition, why is suicide considered a sin? From the perspective of dispassionate scientific thinking, we’re able to understand that value is subjective, and that it doesn’t make rational sense to produce a blanket statement that suicide is bad for a given individual, since the individual may have such a deeply painful experience of life that their best option is to end their existence. Thus we may be quick to contend that the proposition that “suicide is a sin” is incorrect. But in doing so we would be missing the forest for the trees; Christianity says that suicide is a sin not because it’s supposed to hold up under scrutiny when analyzed in isolation, but rather because it compensates for a possible side effect of an additional Christian doctrine: namely that when you die (as someone who is free of sin!), you go to a wonderful world they call “Heaven”. If committing suicide is considered a reasonable choice, then some people might commit suicide to expedite their trip to Heaven. An ideology that gives psychological incentive for arbitrary suicide is bound to be outcompeted in the memetic marketplace by an ideology without that disadvantage.