Sorry, I don't buy it. The experience of atheists isn't different in any real way from the experience of any other human.
The idea that atheists as a group aren't like anyone else because they aren't part of a group is not only logically inconsistent, it is also unrealistic. Atheists are human, and American and some even participate in religious activities.
Humans are social animals. We live in society and makes bonds with people around us. We get our values and world view and ideas about how we fit in the world from the community we are a part of. Religion has nothing to do with this.
If you don't have a sense of community that has nothing to do with whether you believe in God or not. It means you aren't social and there are people of every religious belief that fit in that description. It certainly has nothing to do with atheism.
I was brought up in evangelical Christianity where the "testimonial" is a common ritual where a person talks about how they "came to Jesus". It struck me as a little funny reading similar testimonials about how people "came to Atheism",
Now that we have Atheist testimonials, I suppose this could turn into a kind of Atheist revival meeting.