Not everyone who rejects a religion (or religion in general) rejects the idea of god. They simply reject the version(s) of god that they have learned about, having found them wanting in some way or another. For a short time after my deconversion, I wondered about whether there was a creator. I decided I was atheist when I realized that if the universe was spun off the fingers of some cosmic power who then went about his business and forgot about it, then it wasn't any different from there not being one at all.
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould