I agree with this. One way that I will go further is to say that “understanding of the whole system“ is a pretty fraught phrase. One person‘s holistic understanding is another person‘s gnostic gobble-de-gook. Realistically, they are all essentially just abstractions bounded by a different stopping rule. Just because one person‘s view of the whole system does not include what the GOOGLE engineer writing the code had for breakfast does not mean that that can’t be reasonably included.

The issue I think people have is that abstractions do not announce when they are insufficient or porous. This means that an abstraction which is perfectly trustworthy without further inspection for many years can suddenly become hazardous without warning.