darth_ender said:

atheism is too broad a category to rule it as a religion or not a religion.

Nope, it's real easy. It's not a religion.

Let's say somebody wanted to practice it as such... Where is the Holy-Book? Where are the places of worship? Where is the deity? Where is the religious figurehead? Where are the doctrines? Where are the priests? Where is the organised structure? Where are the forms of dress? Where are the rules? Where is the rigidly defined creation myth? Where is the iconography? Where is the anything that would define something as a religion?

Arguing that it's even vaguely similar is a bit silly.