> Mathematicians informally speak of functions not being defined everywhere in their domain even though it would be more accurate to say that the domain excludes certain points. This kind of talk is fine among friends where there’s an implicit understanding of what detail is being left out and the trust that the details will be made more explicit when necessary. In a more hostile environment, like Twitter, pedants will gleefully pounce on such lapses in rigor.

While not intended as humor, it seems to me that Mr. Cook transformed the topic of his post from the software to the social setting.

Isn't "implicit understanding" the heart of the matter?