As for your hypothesis, the Hacker News community is built around Hacker News and not religion or the lack thereof, so I find it hard to see how it fits in. I would agree that online communities built around religion are of little interest, but only because I find the subject matter so tedious.
If you could flesh out your argument and make it a little more clear, I'm sure you would get better replies from this community.
Personally I try to never judge the people I socialize with based on their beliefs in irrelevant subject matters. But I am an oddity, being born without the seemingly common gene that causes most people to derive pleasure from meddling and prying into the personal affairs of others.