I really wish more people understood exactly what Atheism means. Atheism is not a lack of belief like most think, but rather a belief that there is no god.
So for everyone that doesn't believe in the bible or Christian God (or any other), this is not enough to claim being Atheist. Atheism is just as much a leap of faith as any religion, as you actually BELIEVE something to be true that is unprovable. That there is no and can be no divine entity of any sort.
Now, I don't know about you, but I find this statement almost as arrogant as claiming that the earth is only a couple thousand years old. Knowing that I am but a speck of dust in the infinity of space and time, to claim as fact that there could never have been any entity with any hand in the creation of what we know to exist would be astoundingly naive and arrogant. (whether direct or indirect). Of course I hold very little credence to the idea that anything created ME specifically, that's pretty in-plausible. But the idea that something may have been responsible for assembling the building blocks for life as we know it? Who knows.
What I do know is that I am not an Atheist. I am a believer of the Scientific Method, and by claiming such know it would be hypocritical to claim Atheism.