Comment by handoflixue

Rationalists, in this case, refers specifically to the community clustered around LessWrong, which explicitly and repeatedly emphasizes points like "you can't claim to have a well grounded belief if you don't actually have empirical evidence for it" (https://www.lesswrong.com/w/evidence for a quick overview of some of the basic posts on that topic)

To quote one of the core foundational articles: "Before you try mapping an unseen territory, pour some water into a cup at room temperature and wait until it spontaneously freezes before proceeding. That way you can be sure the general trick—ignoring infinitesimally tiny probabilities of success—is working properly." (https://www.lesswrong.com/posts/eY45uCCX7DdwJ4Jha/no-one-can...)

One can argue how well the community absorbs the lesson, but this certainly seems to be a much higher standard than average.