I too have read Never in Anger, the ethnography mentioned in this blog post, and the way I found it was by reading a survey of egalitarian societies called Hierarchy in the Forest, by Christopher Boehm. Many of the personality traits that the author seems to think are special about people who share the East Asian phenotype are actually common amongst fiercely egalitarian societies. It is normal to highly police socio-emotional expression and to regard angry tribe members with suspicion. The !Kung San live in a hot climate and are like this. The Montenegro Serbs live in the Balkans, a rather different climate, and are also like this. I finished Hierarchy in the Forest with the strong impression that no member of any modern society could tolerate the lack of personal expression required to suppress any would-be chiefs.
This person could've spent a lot less time going down a rabbit hole with a couple introductory anthropology classes and by asking themselves if there were any societies with these same traits in a warm climate. It is poor scientific reasoning not to check for examples of this personality type in hot climates. Not exactly PhD material.