Am I the only person who looks at Jeremy Kun's output and thinks "Nope, this guy is not actually a gifted communicator dedicated to sharing knowledge, he's just a postdoc on an annoyingly self-aggrandizing narcissism trip"?
My point is that there are a lot of people with math PhDs, but Kun is in a small unenviable minority that is driven to engage in self-promotion via all these blog post "primers", which of very dubious pedagogical quality.
I don't know why him spending untold hours producing detailed content is a bad thing. Even if it is for self-promotion.
It's a shame that rather than actually considering the very evident pathology here (i.e. the production of mediocre vanity blog content that serves primarily to improve the author's profile) everyone is either downvoting or nitpicking.