I guess there's a good chance that all the background fluff was on his mind, but he did not spell it out all again, mistakingly assuming everyone would be on the same page as him.
It read to me that he was simply concentrating on the mechanical design, with a focus on communicating with folks that mechanical design going forward was going to be strongly informed by past versions. The article is also in the context of current playtesting, where the monster's "life" would be controlled by the playtest docs, not by the home adventure designer.
I think the big furor over this article, and what it implies for overall presentation of monsters, is based on reading rather too deeply between the lines.