@SchwarzerRitter. Actually the definition of religion is "a set of beliefs concerning the cause, nature, and purpose of the universe, especially when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs". I can write about atheism and explain why it's better than religion, so to convince people to stay by my side, BUT, since atheism is not involved in the sacred/metaphysic dimension, nor in rituals, trying to explain the nature of our world and our morality by rationality, It is not considerable a religion anyway.
But there are atheists who write books explaining why atheism is better than religion and who meet to discuss how atheism is better than religion. Once you start proselytising you turn it into a religion.
It isn't a lifestyle for me. I personally believe atheism is what you make of it. You start by not believing in a supreme being, and you choose where you go from there.
I don't think it's much of a lifestyle, but I believe that that's as close to religion as it should be. Anything farther contradicts the belief itself, making it exactly what the group is against.
But there are atheists who write books explaining why atheism is better than religion and who meet to discuss how atheism is better than religion.
Once you start proselytising you turn it into a religion.