"It does feel to me that most people who share on the deconversion blogs have been deeply hurt, and disillusioned by their experience in the church"Now, bear in mind that my expertise on deconversion is based on two things: my own experience, and what others have said about their experience. For a sampling of what other people have said, I suggest you consult the blog of the late Dr. Ken Pulliam; the topic came up there several times, and he had enough readership to garner a variety of answers. (I mention this so you won't have to take my word for it. Check the comments in particular.)
That isn't an incorrect assessment. I would agree with Grace wholeheartedly on that. Many people have been hurt, though not all. What is overlooked, in my opinion, is that being hurt is just the start. That may be the catalyst to an individual beginning to question their faith, but it isn't the reason that they likely de-converted. They see that something is wrong with the system they've placed their trust in, and it forms a crack. The daylight starts to shine through and they begin chipping at that crack to get more light to shine through. Typically they are looking for the truth, not a way out. But once they start chipping at the crack it gets bigger and bigger until the whole wall is down.
I'd say that's true with any major life change a person has. They begin to realize something is wrong with the way they've been "doing" their life, so they start to search for the right way. Does that make any sense?
I've said already that the process is different for everyone. For some, it begins with a personal or communal slight or betrayal - a sense that their community of faith has failed them in some way. For others, it's a more direct personal crisis - a major disease, an unexpected death, a series of misfortunes. For others it begins with nothing more dramatic than a simple question or two... that don't have easy answers. But, as D'Ma notes, these things aren't the reason people leave Christianity. They're just the catalyst, the spark - or, sometimes, the last straw.
What it almost never starts with - pardon the digression - is the desire to sin freely, without being convicted by the spirit (whatever that means, but I feel safe in translating it loosely as "Atheists don't feel the same sort of guilt that believers do when they sin".) I hear this asserted fairly frequently, but in my experience when Christians really want to sin... well, they don't bother to declare disbelief, first. They just surrender to temptation, and then they either feel guilty and ask for forgiveness, or they drop straight into denial and rationalization to avoid the sense of guilt. They act pretty much like anyone else, in other words. Perhaps more importantly, as a reason not to believe in God, this makes no sense at all - if you know (or believe) that God is omnipotent and omniscient, then why would you think that pretending He doesn't exist would in any way exempt you from his judgement? I'll come back to this later - yes, there's at least one other post before we get to what I think works to make Christianity appealing to former believers - but for now let's get back to our topic.
If you're betrayed by your faith community, but you don't see that as reflecting badly on the Faith, then you simply find another, more compatible, community. You may identify yourself as an ex-Catholic, an ex-Fundamentalist, or even "faithful but not religious" - but you won't consider yourself an ex-Christian. If you go a bit farther, and decide that you believe in God but can't credit Christianity, you maybe become a deist, or maybe a pantheist, or you find some other religion that better suits your social, spiritual, and intellectual needs.
The people who filter down into actual unbelief may have started their questioning because of some particular incident (even if it's just an inability to resolve an apparent inconsistency in their beliefs), but they leave Christianity because it no longer meets their needs - either it can't answer their questions, or the answers point out new, more difficult questions. They - we - end up as unbelievers because none of the other worldviews they encounter seem to offer any better, or more consistent, answers.
It isn't a decision; it's a process... and for the vast majority of people, it's a loss. The most common metaphor I hear, the one people seem to feel is most apt, is the end of a love affair. Did you ever date that One Person? Remember the time when you were sure that it was True Love, that it would last forever because that's what True Love does? And then one day you find yourself alone, and you're wondering what happened - whether something is wrong with you, or something was wrong with them. Or maybe it wasn't true love, but how could that be - you knew, knew that it was, so how could you have been so wrong!? And then you spent all your time brooding over what went wrong, who was at fault, what you could have said to make things come out differently. You talk about it, a lot - and when you aren't moping and depressed, you're angry and bitter: how could they have done this to you?
And eventually your friends get sick of it, and tell you to move on - or maybe you just get tired of listening to yourself whine, of feeling pathetic, of being such a wreck. So you start putting your life back together, a little bit at a time - maybe you find new friends, so you won't have to to be reminded, or maybe your old friends side with your ex and don't want to spend time with you anymore. You reevaluate yourself, your beliefs, your sense of worth; you reassess what you have to offer, and what you want in return.
Almost everyone who's deconverted - at least, everyone I've heard tell about it - has at some point expressed the wish that they could still believe. Often there's some ambivalence. (I wish I was still in love with him. I wish I didn't love him so much.) Anger is almost inevitable: some of it is justified, and some of it is a shield for other emotions, like guilt or grief, that don't seem appropriate anymore.
This is, in no small part, why a lot of unbelievers continue to talk about Christianity - why they continue to define it, refine it, poke at it, see how they feel about it. They're examining the relationship, looking to see where they went wrong, and where their partner failed them, and maybe how much was just basic incompatibility. It's a natural part of the process of grieving. And in time, they move on to other things. Oh, they may come back to it now and then, but the subject just doesn't have that burning urgency anymore.
So, circling back to the original question, I agree that former believers do talk about Christianity fairly frequently, and that this does indicate some concern with the topic - I just haven't seen any evidence that such concern is based in a spiritual need or longing.
 "Deconversion" in this context refers to someone who left their religion for no belief in particular. If they became a Wiccan, or a Buddhist, or Jainite, or something like that, I would refer to it as "conversion" instead. There is some interesting work on the psychology of conversion, and the psychology of deconversion seems to me to be the same in some ways and different in others. I suppose I could spend another post or three in comparison and contrast, but that way madness lies.