[stevelosh]

You meeting some atheists that weren't isolated doesn't mean that isolated atheists don't exist.

The author isn't saying that all atheists are isolated, but rather that there are many atheists that are.

It's like me saying:

"I saw a lot of black cats when driving across the country."

and you replying:

"Nonsense, I drove across the country and saw plenty of white cats but no black ones, therefore there cannot be black cats all over the country."

You said you spend no time around churches. Isn't a church exactly the kind of place an "in the closet" atheist would feel most isolated, and have to maintain the most secrecy?