It's a bit of a trope in the atheist movement to share stories of how you, the free-thinking rational atheist person, came to throw off the shackles of the religion you were brought up in and embrace evidence and all that good stuff. And I'm certainly not here to knock that, since for all that non-belief has come a long way lately it's still fighting against the dominant cultural paradigm, which is to at least pay lip service to the idea of some overseeing deity who made us all, looks out for us, really hates the gays, etc. etc. So the whole solidarity/consciousness-raising thing has considerable value. The Richard Dawkins Foundation, for instance, has a whole page dedicated to converts' stories, and some of them are genuinely inspiring and humbling, particularly to someone like me who never really had much of a journey to make or that many challenges to overcome.
There's an expectation, though, that these conversion stories will all operate in one direction, that direction being from belief to non-belief, and a tendency to scoff at any tales of conversions in the other direction. To be fair, you could certainly argue for some justification for a sceptical attitude towards such stories, given the history of bogus claims of "deathbed conversions" attributed to various historical figures from Thomas Paine to Charles Darwin to Christopher Hitchens, and the rather distasteful affair of Antony Flew, a philosopher and high-profile atheist (well, high-profile in philosophical circles, anyway) who supposedly underwent a conversion to Deism late in life and wrote a book about it - or, rather, a book was written to which his name was prominently attached. As proper rationalists, though, it behooves us not to dismiss these out of hand, since there are undoubtedly people who genuinely do go from a state of non-belief to some sort of belief in some sort of deity, however woolly and ill-defined.
An example popped up on my Twitter feed the other day - that tweet and the ones that follow it give you a flavour of what to expect, but it's worth reading the article that it links to, which is here. Obvious but important things to say: I have no reason to doubt Nicole Cliffe's account of her journey from non-belief to belief, and she herself acknowledges that it happened at a period of some internal personal turmoil. What's fascinating from an atheist perspective is to try to imagine what sort of mental process could have been going on to prompt something like this. It's all too easy to say: well she's clearly had some sort of undiagnosed stroke or something, or GONE FREAKIN' MENTAL in some other way, but if we rule this out, what then? The trouble is that nothing in the article comes even remotely close to explaining something as seemingly (to an atheist, at least) inexplicable as this, something which seems (again, to an atheist) like Tim Robbins standing in that river in the rain for a bit and then voluntarily crawling back up that shitpipe and consenting to be locked in that tiny cell for the rest of his life, and occasionally recreationally bumraped in the showers.
One might also want to ask people who write articles like this: OK then, can you set out in reasonably clear terms what it is you believe, being sure to make a clear distinction between those things you think are actually real, and those which are some sort of metaphor for something which in turn may or may not be real? Read Sarah Perry's essay here, for example, and see if you can suppress your irritation at the inability to distinguish between "story" and "actual thing", nor indeed to grasp the idea that distinguishing between these things might be a useful or desirable thing to do. It's the same sort of thing that Karen Armstrong has parlayed into a whole career of writing books and then talking about them on various media outlets.
But, you might say, as irritating as all this is, these people are not hijacking commercial aircraft and flying them into buildings, they're not throwing gay people off high rooftops, and they're not terrorising already-traumatised women outside abortion clinics, so where's the harm? And I'd mostly agree with you; in general as long as people aren't demanding that their absurd beliefs be used to constrain the actions of others in some way (e.g. by killing them, in the most extreme cases) then I guess you can believe what you like.
It would still be better for the people concerned, though, and to a lesser extent for everyone else, if they didn't believe absurd stuff, just because of the general desirability of what you might call good epistemic hygiene. A sort-of analogy might be: if you don't wash your hands after having a shit, the person you're most likely to make ill is you, so maybe it doesn't matter to others. But there is a good chance you'll make your children ill, if you have them, and a smaller chance of infecting other people. Plus, once you've diverged from good sense, where do you stop? Who's to say that in a few months you won't just be shitting on the floor? What principle tells you that not washing your hands is OK, or even desirable, but shitting on the floor isn't?
I suppose the other aspect is just that I'm more inclined to sympathise with someone clinging to religious thought in, say, Iran, where access to material (books, the internet, other people) that might facilitate an escape from religion is heavily restricted and the consequences of public atheism much more severe, than with people doing so in a liberal western democracy, albeit one where, ridiculously, we still have an unelected head of state and religion remains embedded in our government and legal systems, but nonetheless one where the consequences of "coming out" are generally minimal. There's also this notion that agnosticism as opposed to atheism is the more "sophisticated" position to take, whereas in fact all that does is demonstrate that you know nothing about science or philosophy, in particular the branch relating to how knowledge is acquired.
So, basically, what I'm saying is: this tweedy wishy-washy sort of religious belief may be safe for discussion at your next Church of England coffee morning, but don't let your guard down too far as someone could shit on the carpet at literally any moment.