But we all know such systems already: for instance, people! No, this post is a supplement/subsidiary to the previous one ("Computers can be understood" — BTW here's another recent blog post making the same point: https://jvns.ca/blog/debugging-attitude-matters/), carving out exceptions to the general rule, and illustrating concretely why these are exceptions (and what works instead). It is useful to the practitioner as a rule-of-thumb for having a narrow set of criteria for when to avoid aiming to understand fully (and alternative strategies for such cases). Otherwise, it's very easy to throw up one's hands and say "computers are magic; I can't possibly understand this".
(The point of the article here is obvious from even just the first or last paragraphs of the article IMO.)
The fact that you didn't pick this up leads me to think you are more interested in being smart than helpful, but perhaps I am wrong about that.