I think that this emphasis on explicit, built-from-scratch mathematical proofs runs counter to your previously expressed suggestion that learning via pattern matching is more efficient than learning via explicit reasoning.

I've found that the emphasis on first principles is often symptomatic of someone who is speaking for their own benefit rather than that of their audience. After all, you're making the unwarranted assumption that A.) your audience wants first principles rather than a practical application, and B.) your audience is, for lack of a better word, too dumb to derive these principles for themselves. It's very easy to convince yourself that you are giving the audience the tools they need to understand what you're saying, when in fact, you're using the audience as a sounding board to help yourself better understand what you're actually saying.

(By the way, I'm using the "royal You" rather than specifically singling out you, Jonah. You caution against this very thing in another post of yours. ).