>This is a label applied from outside

I don't think this is accurate. Most rationalists seem to self-describe as rationalists, and talk about rationalism as a "thing".

There is some dogma, sort of, in the form of The Sequences. (An extraordinarily goofy name that belies some of the mysticism-adjacent LARP that sought to treat the ideas as revolutionary. I suspect a 20 year old was behind it.) I say "sort of" dogma because people are aware that the studies referenced in there turned out not to replicate and have generally abandoned them. But you still see some references to them and vague reverence of them.