You may not hold Atheism as a religion, but from what I have seen in these forums, I see people form beliefs that they can't verify as necessarily true (just like beliefs of God), and I have seen these people hold these beliefs with faith as strong as any religious person I have ever seen.
The level of emotionalism seen consistently here by the atheists matches the level of emotionalism by theists, which indicates a strong attachment to the respective belief systems.
Just as people claim that music is their religion, politics is their religion, sex is their religion, so too atheism for those who post here seems to fit the same criteria.
Atheism denies the truth of God, not the truth of religion.
The key component of a belief that brings it to the level of religion is the repetitive practice of that belief in the face of opposition, and the emotional investment beyond a pure intellectual belief.
The difference between having a heart felt soulful belief in something and simply holding an idea in the mind about something is the difference between a computer and a human being. A robot could be programmed to perform all the external and measurable actions of a particular religion, you could have a robot priest perform mass, give confession, be seen externally praying.....but no one would say that a robot is actually practicing the Catholic religion because of the external acts.
It is this internal relationship between a person and their ideas, whether they are invested emotionally or not that ultimately determines their religiosity toward their beliefs...their passion concerning their beliefs, and their attachment to their beliefs.
Quote from Cutten:
Just because X is granted the same legal protection as Y, does not mean that X is identical to Y or even of the same category. Atheism is not a religion by any accepted definition of the term. Atheists don't gather at places of worship, they don't have a fairly uniform moral code that they preach to atheists "non-believers", they don't worship a divine being, they don't have any sacred texts, they don't have any centralised institution or religious leaders whose teachings they follow. The only thing atheists have in common is a belief that there is no divine being or beings. By definition, something that denies the truth of religion cannot be a religion.
All religions are beliefs, but not all beliefs are religions. Atheism is a belief, and not a religion.