It’s hard to write a rigorous analysis of something without length. The challenge is keeping it interesting.
You can take the truthest truth ever like "god does not exist". This statement is rationalist and true and short so the author is supposed to cry with a tears of happiness. But making a wisard to behave like this requires something more thorough to be sent. Maybe the author's post also has a chance to become a rationalist if it would be a little bit... longer?
The assumption that “stupids” are going to be more receptive to long-form/from-first-principles arguments is wrong, I think. So is the assumption that that’s why rationalists write that way (it’s more likely because of bubble culture and/or because people like hearing themselves talk).
What makes you think the author has poor reading skill?
I'll cite an example: https://www.lesswrong.com/posts/qDmnyEMtJkE9Wrpau/simulacra-.... I can make the case that one might feel smarter simply having read through the grating writing.