I think most people would parse "rational thinking community" as a community interested in rational thinking, similarly to how you'd parse Python community as a community interested in Python rather than one that was implemented in Python. English is generally very prone to ambiguity, and if there's a valid interpretation of what someone said that makes sense it's usually best to assume that's what they meant unless further evidence indicates otherwise.
I think most people would parse "rational thinking community" as a community interested in rational thinking
You are right, it would have been wiser to apply grace and ask to clarify why he was in such wonderment at the existence of a "rational thinking community".
However, my concern was merely that the phrase "rational thinking" carries with it all sorts of implicit assumptions about the "rightness" or "wrongness" of what is being discussed, and it's important that when joining in a presupposed community of "rational thinkers" that this does not carry the assumption of "well, these people claim to be rational thinkers, therefore they are holders of the truth"
The context of his surprise at the existence of a "rational thinking community" gives us a hunch at this potentially incorrect presupposition, but we can't know.
