>implying atheism is a religion
It technically is. If someone asks you what religion you are, do you just sit there with a blank face and not respond, or do you reply "I'm Atheist."
If religion is defined as a set of beliefs, then the word atheism literally means that one doesn't worship or follow any divine or supernatural beings. In other words, they believe no supreme beings exist. Which is a belief.
The word religion doesn't imply that you actually practice the religion, even if you belong to it. All religion is is a set of beliefs, and sometimes culture and morals.