You can certainly learn a bit about how a company thinks about UX, accessibility, and its users more broadly by looking at its error messages. Although I didn't care for much of the specifics proposed, I am glad about this post as I think it is important to think through error messages with intention and treat them as products in their own right.

Regarding the proposed "good" alternative, it has less actionable information than the original "bad" message, depending on what the product is and who its users are. In particular, you can't determine whether "fetch data" is impenetrable jargon without looking at the product itself and its users.

I also frequently see people use the designation of a user as non-technical as an excuse to dismiss their intelligence. It's true that tech folks generally underestimate how confusing computers and software are to the average person, but erring too heavily in the other direction also has negative impacts for accessibility. Either way, you can at least hide away that extra detail, with jargon and all, using that link tip she mentioned.

Finally, this writer seems to overestimate the extent to which most users view "contact Customer Care" as "giving them a way out" and not an invitation for further aggravation.