I'm not really sure if Noisy Rhysling actually believes what he seems to argue here. Yes, societal pressure might make people respond differently about their religiousity than what they actually believe. There are probably more non-believers in Iran than what official statistics would suggest. Conversely, the people of China is probably more religious than what official statistics suggest.
But there is also no doubt that humans are by nature magical thinkers, and religion being a subset of magical thinking, there is very good reason to believe that there are billions of honestly religiously believing people around the world.