The reason people are annoyed by it isn't because they don't understand it, it's because he's condescending and self-righteous, it's moralizing.
People make all sorts of things their identity and that's fine, but there's some sort of lack of curiosity that makes them a little less interesting imo. A candy bar isn't good for you, but people enjoy them on occasion. That's true of a lot of things in life.
The majority (but not all) people I've known in this category have been mormons, obviously people can do as they wish, but it's often other beliefs driving this with after the fact reasoning applied vs. some epistemically consistent model.