Since there are no clerics in Dark Sun, I don't think that will be a problem.
Says you. My DM is running the ever popular "Bringing gods back to Athas" campaign. Heck, my group has a Cleric AND a Paladin plus a Monk who MCed Cleric all worshiping Pelor. We have Team Pelor and Team Heretic heh. Conveniently, we sit around the table perfectly divided. Here is the Divine Characters sidebar from the DSCS:
"DIVINE CHARACTERS
The gods who once influenced Athas are long dead and
nearly forgotten by the people of the world Therefore,
heroes who draw on divine power are rare indeed. You
won’t find temples or priests of your god. You’ll probably
never meet another person who believes in any god. Still,
if you really want to play a divine character, you and your
Dungeon Master might be able to make it work. Here
are some suggestions for how your character might know
about divine magic and gain access to divine powers.
+ You have come to own a relic from an ancient age
that grants you odd powers. You’re unsure of its
origin or what the strange symbol emblazoned on
the relic’s surface represents.
+ You are a descendant of a long-forgotten demigod
whose lineage has survived across the centuries. You
draw divine power from your holy blood, disguising it
as psionic or primal magic to keep your secret safe.
+ Wandering in the wastes, lost and dehydrated, you
collapsed and heard a voice that promised to save
you in exchange for your devotion. You awoke in a
tribal camp, parched and burned but alive. You can’t
be sure exactly what saved your life, but you do your
best to hold to the bargain you made."
Plus given that they added the Dark Sun box to the CB to allow people to make any kind of character and still play it w/all the Dark Sun gear and options, I think that kind of kills the whole No Divine thing. As far as the official word for the campaign world, yes no gods. It's always been DM discretion in 4E and in 2E you still had Clerics, they were just elemental focused instead. They could have easily done that in 4E as well.