> By the same token, the ability to dismiss an argument with a “that sounds nuts,” without needing recourse to a point-by-point rebuttal, is anathema to the rationalist project. But it’s a pretty important skill to have if you want to avoid joining cults.

Aka as "common sense". It seems like these people make small errors in their base assumptions or reasoning. Over time, as these mistakes compound, they can lead to increasingly bizarre philosophies. Common sense might serve as a safeguard against such pitfalls, but it is frowned upon in those circles.