I just realized that while this is my argument for why I don't think theists are categorically irrational, it doesn't mean that any of them would belong here. Less Wrong obviously values having an accurate map not just to the extent that it facilitates "winning", but also for its own sake, because they value truth. So finally I would qualify that the argument against having theists here isn't that they're so necessarily irrational, but theism conflicts with the value of having an accurate map. Likewise, Less Wrong might value certain epistemological foundations, such as Occam's razor (obviously) and any others that lead to choosing many worlds as the natural hypothesis.

I just forgot (while composing the message above) that 'Less Wrong' represents a combination of instrumental rationality AND VALUES. I usually think of these values as valuing human life, but these values include valuing epistemic rationality. While Less Wrong is much more tolerant of different values than wrong beliefs in general, its justifiably not so tolerant of different values about beliefs.

I think that my comment above should have been down-voted more than it was, since it's not representing the community norm of valuing truth for its own sake. I'm not valuing truth so much these days because I'm going through a value-nihilistic phase -- that ironically, I blame on Less Wrong. But 'you guys' that care about truth might down-vote a comment arguing that there is no value to beliefs beyond their effectiveness in achieving goals.