Particularly padding and margins - I’ve only recently taken the time to study what makes a design look good vs looking off in terms of spacing, and have come to similar conclusions as the author.
I suspect if the rule against pure black on pure white were buried in the middle (or omitted) then the response would be warmer.
I'm not sure why it's so controversial among digital designers.
The same person taught me that "optical alignment is often better than mathematical alignment" (which is why the bottom of curved letters often falls slightly below the baseline if you look closely).
Assuming you're talking about the "Give me #000000 on #FFFFFF or give me death!" crowd, it's a kneejerk reaction to the cardinal sin of gray-on-gray content that is fucking impossible to read.
I happened to have a few iOS apps where true black is an option (which is desirable on OLED to save battery). A perhaps less common concern is eInk whose dynamic range is quite limited and for which #000000/#FFFFFF greatly enhances readability.