Atheists have a reason for not believing in God. It's a conscious decision.
Not necessarily. I think we are all born atheist. It's what we learn from home and society that molds our views. Many people decide that those views don't fit their perceptions and they decide to discard their learned systems and choose to be atheist.
there are people who don't believe in God simply because they can't be bothered
This is true and I admire them for not having to carry the baggage. My wife was born and raised in old East Germany where no religion was ever taught or even discussed. When she escaped to the West she was confronted with the concept of god and systems of belief that were so foreign that the concept of god had to be explained. In the explanation no one could define god so she dicarded the idea as insignificant to this day. She's probably the ultimate ignostic atheist. Bliss.
Do you think that every single of the hundreds of millions of non-believers on this planet became an atheist because of a philosophical argument?
No, I think they were atheist from birth. Some learned false information and decided to discard it and others never learned it to begin with. There probably are some who were able to completely expunge the idea of god so well that they really don't care anymore and that is a pretty wonderful condition after being brainwashed as a child.
From what you've written I get the opinion that you do think the statement you asked above is true. ???
Also we're mixing up two different concepts here: "religion" as in "belief" and "religion" as in "an organized community of worshippers".
Are we? I think part of my original point is that the poll is mixing the catagories in a way that the concept is invalid. Nones can mean many things. Belonging to organized communities of worshipers can mean many things, other can mean a lot. The condition of being atheist encompasses all of the catagories or none of them and in reality is not part of the poll at all. It's just ambiguous.