This post raises a whole constellation of connected questions, so here are my thoughts on all of them:
If the question is "Can Wednesday be religious and still be a smart person who's good at using rationality?", the answer is empirically yes (eg Robert Aumann).
If the question is "Can we still call Wednesday rational if she's religious?" the answer is to taboo "rational" and let the problem take care of itself.
If the question is "Is it okay for Wednesday to be religious?" the question is confused in the first place and any answer would be equally confused.
If the question is "Should Wednesday choose to believe religion?" the answer is that you don't voluntarily choose your beliefs so it doesn't matter.
If the question is "Should Wednesday, while not exactly choosing to believe religion, avoid thinking about it too hard because she thinks doing so will make her an atheist?," then she's already an atheist on some level because she thinks knowing more will make her more atheist, which implies atheism is true. This reduces to the case of deception, which you seem to be against unconditionally.
If the question is "Should I, as an outside observer, do my best to convince Wednesday religion is wrong?" the answer depends on your moral system. I'm a utilitarian, so I would say no - I think it's a background assumption here that she's happier being deceived. I know you're not a utilitarian, so you'd have to work it out in whatever system you use.
If the question is "Should we at Less Wrong exclude all theists?", my answer is of course not. If they want to come here and talk about prisoners dilemmas or the Singularity or something, then of course we should welcome their opinions.
If the question is "Should we at Less Wrong tell all theists they can't talk about how great religion is?" my answer is a qualified "yes". Not because we specifically hate religion, but for the same reason we don't allow posts explicitly about politics. There are places for those debates, this isn't one of those places, and having them completely changes the feel of a community and saps its energy.
If the question is "Should we at Less Wrong stop acting like atheism is an open-and-shut case?," my answer is "no". Sometimes in order to move on, we've got to accept certain assumptions. For example, even though there are a few hard-core steady state theorists out there, most astronomers have accepted the Big Bang as a default assumption because they can get more done by building on Big Bang theory and working out its exact implications then they can debating the last few steady-staters ad nauseum or refusing to even mention the beginning of the universe because it might exclude someone. Christians work in exactly the same way; when they want to discuss obscure points of theology, they start from the assumption that God exists and work from there, although they'll discard that assumption when they're debating an atheist. I don't hold it against these Christians - they'd hardly be able to do theology without it - and I hope they don't hold it against us.
If the question is "Should we at Less Wrong stop saying mean things about religion?" then my answer is that we should never deliberately say mean things just for the sake of saying mean things, but that if it's absolutely necessary to condemn religion to make some greater point (like to use it as an example of a bias towards anthropomorphism) then it's not worth refraining from it to prevent potentially some hypothetical theist from feeling excluded. However, writers should make sure to phrase it as neutrally and non-insultingly as possible, something atheists are generally bad at.
If the question is "What kind of person would name their daughter Wednesday?", I have no good answer. Maybe someone who really, really liked the Thursday Next books?
Also, this wins my prize for most intriguing title on LW so far.
Sorry for doing such an insane necro here, and I'll delete if asked, but I don't think this is right at all. Broadly, in the real world, I accept the premise "avoiding listening to opposing positions is bad." I do not believe that "if you really don't think you could stand up to debate with a talented missionary, maybe you aren't really an atheist" because I don't think it scales up.
I am a human, I have mechanisms for deciding what I believe that are not based on rationality. I have worked very hard to break and adapt some of those mechanisms to alig...
(Disclaimer: This post is sympathetic to a certain subset of theists. I am not myself a theist, nor have I ever been one. I do not intend to justify all varieties of theism, nor do I intend to justify much in the way of common theistic behavior.)
I'm not adopted. You all believe me, right? How do you think I came by this information, that you're confident in my statement? The obvious and correct answer is that my parents told me so1. Why do I believe them? Well, they would be in a position to know the answer, and they have been generally honest and sincere in their statements to me. A false belief on the subject could be hazardous to me, if I report inaccurate family history to physicians, and I believe that my parents have my safety in mind. I know of the existence of adopted people; the possibility isn't completely absent from my mind - but I believe quite confidently that I am not among those people, because my parents say otherwise.
Now let's consider another example. I have a friend who plans to name her first daughter Wednesday. Wednesday will also not be adopted, but that isn't the part of the example that is important: Wednesday will grow up in Provo, Utah, in a Mormon family in a Mormon community with Mormon friends, classmates, and neighbors, attending an LDS church every week and reading scripture and participating in church activities. It is overwhelmingly likely that she will believe the doctrines of the LDS church, because not only her parents, but virtually everyone she knows will reinforce these beliefs in her. Given the particular nuances of Mormonism as opposed to other forms of Christianity, Wednesday will also be regularly informed that several of these people are in a position to have special knowledge on the subject via direct prayer-derived evidence2 - in much the same way that her parents will have special knowledge of her non-adopted status via direct experience when she wasn't in a state suitable to notice or remember the events. Also, a false belief on the subject could have all kinds of bad consequences - if the Muslims are right, for instance, no doubt Hell awaits Wednesday and her family - so if she also correctly assumes that her parents have her best interests at heart, she'll assume they would do their best to give her accurate information.
Atheism tends to be treated as an open-and-shut case here and in other intellectually sophisticated venues, but is that fair? What about Wednesday? What would have to happen to her to get her to give up those beliefs? Well, for starters, she'd have to dramatically change her opinion of her family. Her parents care enough about honesty that they are already planning not to deceive her about Santa Claus - should she believe that they're liars? They're both college-educated, clever people, who read a lot and think carefully about (some) things - should she believe that they're fools? They've traveled around the world and have friends like me who are, vocally, non-Mormons and even non-Christians - should she believe that her parents have not been exposed to other ideas?
Would giving up her religion help Wednesday win? I don't think her family would outright reject her for it, but it would definitely strain those valued relationships, and some of the aforementioned friends, classmates, and neighbors would certainly react badly. It doesn't seem that it would make her any richer, happier, more successful - especially if she carries on living in Utah3. (I reject out of hand the idea that she should deconvert in the closet and systematically lie to everyone she knows.) It would make her right. And that would be all it would do - if she were lucky.
Is it really essential that, as a community, we exclude or dismiss or reflexively criticize theists who are good at partitioning, who like and are good at rational reasoning in every other sphere - and who just have higher priorities than being right? I have priorities that I'd probably put ahead of being right, too; I'm just not in a position where I really have to choose between "keeping my friends and being right", "feeling at home and being right", "eating this week and being right". That's my luck, not my cleverness, at work.
When Wednesday has been born and has learned to read, it would be nice if there were a place for her here.
1I have other evidence - I have inherited some physical characteristics from my parents and have seen my birth certificate - but the point is that this is something I would take their word for even if I didn't take after them very strongly and had never seen the documentation.
2Mormons believe in direct revelation, and they also believe that priesthood authorities are entitled to receive revelations for those over whom they have said authority (e.g. fathers for their children, husbands for their wives, etc.).
3I have lived in Salt Lake City, and during this time was, as always, openly an atheist. Everyone was tolerant of me, but I do not think it improved my situation in any way.