I think there are different ways to interpret what a popular opinion is. For instance, there is doing thing X, wanting to do thing X, and wanting to want to do thing X. So even if a religious concept appears unpopular, it’s possible that believers of a religion want to express that concept, or even want to want to express that concept, even if they don’t directly express that concept in their everyday lives.

I think abortion is a good example of this. Plenty of people who oppose abortions have had abortions themselves.