I'm asking, is that actually necessary? I suppose you're saying that yes, it is impossible for rationality and religion to coexist, and that's why there are very few theistic rationalists.
A rationalist should strive to have a given belief if and only if that belief is true. I want to be a theist if and only if theism is correct.
Note also that getting the right answers to these sorts of questions matters far more than some would estimate. If Jack Chick is correct, then most people here (and most of the world) is going to burn in hell unless they are saved. And this sort of remark applies to a great deal of religious positions (less so for some Muslims, most Jews and some Christians but the basic point is true for a great many faiths). In the other direction, if there isn't any protective, intervening deity, then we need to take serious threats to humanity's existence, like epidemics, asteroids, gamma ray bursts, nuclear war, bad AI, nanotech, etc. a lot more seriously, because no one is going to pick up the pieces if we mess up.
To a large extent, most LWians see the basics of these questions as well-established. Theism isn't the only thing we take that attitude about. You also won't see here almost any discussion of continental philosophy for example.
So is LW for people who think highly rationally, or for atheists who think highly rationally? Are those necessarily the same? If not, where are the rational theists?
A rationalist should strive to have a given belief if and only if that belief is true. I want to be a theist if and only if theism is correct.
You're assuming that "no God" is the null hypothesis. Is there a good, rational reason for this? One could just as easily argue that you should be an atheist if and only if it's clear that atheism is correct. Without any empirical evidence either way, is it more likely that there is some sort of Deity or that there isn't?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.