That statement makes me sick. So horribly incorrect.
I'm tempted to guess that the author spends a lot of time around religious groups and churches, and thus, doesn't see many atheists on a daily basis.
I, on the other hand, spend almost no time around churches, and when I traveld across the USA 4 times in the past 3 years, I met a lot of atheists - and they definitely weren't in isolation.