You have now met the crazy aunt we try to keep in the attic. That we’re stuck with them is a long story. Don’t worry, they’re not going to launch any religious wars against unbelievers, they prefer to fight other Jews.
Incidentally, only the modern parts of their beliefs come from the Middle Ages. The roots are much older than that. For centuries, they’ve lived in a mental ghetto that began with a physical ghetto.
Never forget, one of those guys made a ruling that Crocs shouldn’t be worn on the Sabbath because they’re too comfortable. That alone should give you a perspective on them.