putting aside that MS is too huge to even just know about the names of your senior engineers across the globe and that the mail might have gone directly to spam
there is still the issue that this might have been classified as "a crazy letter"
a lot of the article reminds me of people which might (or might not) have competency but insists they know better and are very stubborn and very bad and compromising on solutions. The subtext of the articles is not that far afar from "everyone does everything wrong, I know better, but no one listens to me". If you frame it like that it very much sounds like a "crazy" letter.
Strictly speaking it reminds me a lot about how Pirate Software spoke about various EA related topics. (Context: Pirate Software was a streamer and confidence man who got complemented up due to family connections and "confidently knew" everything better while having little skill or contributions and didn't know when to stop having a "confidently bad" opinion. Kinda sad ending given that he did motivate people to peruse their dream in game design and engage themself for animal protection.).
Or how I did do so in the past. Appearing very confident in your know-how ironically isn't always good.
And in case it's not clear: The writing reminding me of it and having patters of someone trying to create a maximally believable writing to make MS look bad doesn't mean that he behaves like that or that the writing is intended to be seen that way.
It's more about how we have a lot of "information" which all look very believable, but in the end miss means to both: Verify many of the named "facts". And, more importantly, judge the sentiment/implicit conveyed information.
Especially if we just take the mentioned "facts" without the implicit messages and ignore the himmanagement communication issues I would guess a lot of that is true.