Read the comments below the article since there are plenty of level-headed atheists there that say the same thing I did here.
I said it once and I'll say it again- I honestly am perplexed as to why the christians here are trying to show how atheism is a belief system. It's not. Neither is theism. Plain and simple. The fact that the christians here are trying to find work-arounds and such are really just grasping at straws and it's really getting ridiculous.
"Atheism is not a belief system. Atheism is not a religion, an ideology, a world view, or anything like that. If this seems wrong, consider the fact that theism is also not a belief system, religion, ideology, world view, or anything like that. Theism and atheism are single data points or positions: theism is the presence of a belief in the existence of at least one god of some sort, atheism is the absence of any sort of belief.
While theism is not a belief system, many belief systems are theistic in that they contain or rely upon theism. Christianity is a theistic belief system (specifically, a theistic religion). Many new age belief systems are also theistic.
All the same is true about atheism: while atheism itself is not a belief system, there are many belief systems which are atheistic. Objectivism and Humanism are atheistic philosophies. There are also atheistic religions: Religious Humanism, Raelians, Ethical Culture, some forms of Buddhism, etc.
When atheism is described as a belief system, a common error is made, but it is an error nonetheless. If you want to talk about logic, there's a simple observation that might make it clear for you. If "atheism" is a "belief system," then you should be able to point to the single belief system that is shared by all Objectivists, communists, liberals, conservatives, Buddhists, Raelians, anarchists, Religious Humanists, Secular Humanists, Jews, and libertarians who are atheists. What is that belief system? What are it's various premises, positions, doctrines, propositions, etc.?
If not believing something is, itself, a belief system then we can now say the unemployed are hard at work at not having a job, the impoverished are well invested in having no money, the homeless are dwelling in their spectacular non-homes and the hungry are gorging themselves on no food?"