I think that poster has got an obvious agenda, and (s)he doesn't really care about honesty all that much... :S
Speaking as a former atheist who actually does, though? Just in case you want my input? :)
I never did have any "doubts", per se. Not in the sense of thinking: "oh, maybe God is actually real! I've arrived at a crisis of atheism now, ZOMG, n000es!!" :-P But in retrospect..? I have realized that I WAS indeed deeply yearning for something more! Although I did not, at the time, recognize that as being in any way a spiritual thing. And it was not at ALL at the level of conscious "doubt", or at the level of my intellect! All of the arguments still made sense, and did NOT add up in the favor of theism, as I had previously conceived of it. And then sh*t happened. Almost like a bomb going off, and my whole reality got ripped into pieces. And that very deeply changed everything inside of me, and all my concepts of.. well.. everything. Forever. And it was not at ALL a rational thing! It had no use for any arguments! It was all EXPERIENCE, and it was beyond words of any kind.. Still is, mostly. Although I've found a few. Because as you might have figured, I'm a very verbal person, and my brain was just sort of like: "WTF?!" for a few weeks there, from not having any words at all. :-P
..So no conscious doubts. But more like a deep inner seeking/yearning. Which actually, again, in retrospect..? I think has always been with me, in some form or another! It has basically defined me.. And me being such a vocal atheist, for many years..? Was also a part of that extended search for answers, and something deeper, actually! And when you have that mindset, to start with..? And then you add really powerful psychedelics, at high dosages, to that mix..? Of course something like that was going to happen! Which, again, in retrospect, (*les shrugs*), I now see that that was EXACTLY what I'd subconsciously hoped for, and wanted! Like: "f*ck this stupid, solid, predictable, meaningless, black-and-white reality! I'll take ANYTHING that's beyond it.." And I got more than what I realized I'd bargained for.
..I'm not going to say I've got NO agenda. Because really, I think we ALL do! But honesty, openness and transparency..? Is at the very least a HUGE part of mine! I don't want to deviously try to undermine you guys' viewpoint, or any such thing at ALL.. I'm just me! And this is just what I experienced! And I realize, I probably started out from a rather different place than a LOT of people! And probably, before any of the aforementioned experiences, or anything, my brain already worked rather differently from that of the average atheist on here! Which is why so many of you guys can be COMPLETELY satisfied with just the physical world, and feel no need for anything else... While I? I just simply wasn't wired that way. And decidedly am even less so, now. So.. that was just how the cookie crumbled, and things. :)