I mean, it does sound really out there. But especially without having much background, I'm not willing to immediately write it off. These types of places do exist, especially in "off the grid" religious communities that basically self-police. If this is legit, the person involved needs to be believed and needs resources to get out.
What doesn't really line up for me is how someone in one of those communities is routinely online, let alone on an atheist forum, spewing quite a bit of hard-line hate.