I mean religion is pretty much just the concept of defining the relationship between us and the Universe we live in. God is the Universe. Atheism is all about being pedantic about meanings of the words God and Universe. Usually it’s just people that were in a radical religious sect that believes that scriptures are literal and atheists reject all religion because they think that what they were taught in Sunday School as a child is the totality of religion.

If you’re in an atheist that feels the need to join an atheist discussion group tho constantly reinforce your “non-belief” you kind of out yourself as a radical atheist.