Comment by ameliaquining

IIUC the name in its current sense was sort of an accident. Yudkowsky originally used the term to mean "someone who succeeds at thinking and acting rationally" (so "correctism" or "winsargumentism" would have been about equally good), and then talked about the idea of "aspiring rationalists" as a community narrowly focused on developing a sort of engineering discipline that would study the scientific principles of how to be right in full generality and put them into practice. Then the community grew and mutated into a broader social milieu that was only sort of about that, and people needed a name for it, and "rationalists" was already there, so that became the name through common usage. It definitely has certain awkwardnesses.