Look at it this way....A New Yorker will differentiate from a non New Yorker as religious differentiate from non religious
And maybe even pigeon hole them as you are attempting to do with atheism
Imagine you are creating an online dating app in which users need to fill in a profile so that they can be matched up with other users.....
A dating profile cannot contain everything about each user it would just feature certain highlights of its users identity
It may very well ask "home town". "occupation", "sexuality", or "religion" - as well as things such as smoker status or whether or not you drink
These would be relevant to matching people up
I'm pretty sure that one's "been to New York City status" would not feature on user profiles if you were in charge of such a dating service???
"I only date people who haven't been to New York!"
My point is this: One's religion is an important dimension of one's identity and personhood whether you believe in God, Gods, or no Gods
That's how society works
And that some dimensions are more relevant than others
For instance when it comes to online dating one's preference when it comes to dogs vs. cats is perhaps less important than one's smoker status but more important than whether you prefer to use pens with blue ink or black ink....
That's simply the way things work
Maybe you'd disagree with this example but I hope you'll take my point that for any given purpose some personal characteristics are more important than others
For instance, one's medical records lists height, weight, blood type and sex - it does not feature your favourite music, your favourite films, or your favourite food as that would be irrelevant for medical purposes
Although granted, to return to the dating app, if there was something in your life that's very important to you then you could always mention it in some kind of self description field