I think that is what most posters are thinking of "atheists" as: people who don't think the gods are "gods", but just powerful beings that don't deserve worship. I suspect what is driving most of this thread is people's feelings on real world atheism which really isn't comparable.
As for myself, I agree that most good beings would take up the opportunity to "keep fighting the good fight" if offered that in the Fugue Plane, regardless if they thought the god was a god or not (I don't think I have read anyone arguing that the atheists think the good-aligned gods aren't good, just not gods). It seems like that is half the point of having high level archons/guardinels/eldarin. You might have to say you are cool with Tyr to get out of the Fugue Plane, but you spend your time fighting in Raziel's legions instead of singing hosanna's.....
A related thing is that some folks have indicated that they don't think the Powers are worthy of their devotion and faith. And I think that there may be some that would have that perspective in the Realms. Whether that damns you to the Wall or not, I don't know. I don't think that's enough.
But I also think the concept of worship, faith, and even acknowledgement of the Powers is very different in the Realms. They know they exist, and they know they have particular areas they control. I don't think there would be a single farmer anywhere that would feel put upon or oppressed with the concept of saying a prayer to Chauntea before planting seed.
'I'm planting my crop this year, but I'l be damned if I'm going to ask that unworthy Chauntea for help! How dare you tell me that I must believe you exist.'
Seafaring people seem to be superstitious by nature anyway, why wouldn't they invoke Umberlee's name by a simple matter of course?
That's part of why I don't think the concept that the Powers demand you worship is there either. It's a more symbiotic relationship - they need you to survive, and you need them to have an afterlife. They are busy living their cosmological life, fighting their cosmological battles. The clerics, paladins, and non-classed or other-classed clergy are the ones that do the majority of the heavy lifting in the material world. Those are the beings that the Powers are concerned with influencing.
With mortals having free will, all they can do is hope that you'll not get taken by Cyric or Bane, and that you'll end up maintaining the balance in favor of good in the afterlife. Because I think that in the general cosmology, good is the greater and more plentiful force. And the power of that cosmology is the domains of the Powers which is directly related to the number of faithful, both in mortals on Faerun, and souls living in their domains.
The Realms doesn't have the scientific knowledge or background, nor have they had a Dark Ages, or even religious wars. There isn't a need for a renaissance or the enlightenment to question the nature or need for religion or the Powers. People don't preach that 'your God doesn't exist,' they say 'mine is better.' I don't think the concept of atheism as we know it even exists on the Realms.
That's why I think the Wall is populated primarily with evil types. They don't just forsake the Gods, but their culture, their civilization entirely. It's not a 'you don't exist' because they clearly do, nor even simply 'you aren't worthy.' It must be more along the lines of actively trying to undo the very nature of the Gods, and thus the Realms itself. Essentially the endless line of people who think they can do better than the Gods, or become one themselves. Your classic power-hungry villain who's 'going to rule the world! Bwa-ha-ha-ha!'
Ilbranteloth