Flippant response: "It only takes 20 years for a liberal to become a conservative without changing a single idea." - Robert Anton Wilson.

Less flippantly: yeah, I tend to read that wing of progressivism as puritanism turned inside-out. It's not Conservative but it's very conservative, in the context of Haidt's analysis. It has a lot in common with Leon Kass's "wisdom of repugnance".