the growth of conservative (theologically) churches

Attraction to tougher teaching presumably signals something credible about truth/Truth.

I can think of at least two potential exceptions:

1.) If the tougher teaching is targeted at "the other", this might appeal to a certain type. But if targeted at oneself, why would one go-- aside from the belief that it speaks to what is Real?

2.) If I want to be in a community of like-minded, like-moraled people, then there could be some advantages of joining, pretending to adhere, and benefiting as a free rider within the community. This is quite possible theoretically, and we observe some of this, but it's unlikely that it would explain the whole thing-- or even a highly significant part of it.

Here's Joseph Bottum in First Things, citing economist Laurence Iannacone's seminal and "fascinating" 1994 essay, "Why Strict Churches Are Strong.”

Iannaccone insisted that the stricter forms of religious life have benefits that looser and more liberal churches do not. Considered purely in economic terms, he wrote, religion is “a ‘commodity’ that people produce collectively.” Precisely because the personal costs are so high, a strict church soon loses “free riders,” the people who take more than they give. And the remaining members find a genuine social community: a tightly knit congregation of people who are deeply concerned with one another’s lives and willing to help in time of need. They gain something like ­intellectual community, as well—a culture of people who speak the same vocabulary, understand the same concepts, and study the same texts.

More recent research, following Iannaccone’s path, has added demonstrations that the best way for, say, a poor woman to improve her social and economic class is to join an active and strict church. The chances of forming stable marriages will be increased for both herself and her children, the probabilities of being drawn into crime and drugs will be decreased, and even her opportunities for employment will be raised.