The argument here doesn't hold up for me.

The author states "The formality and authority of serif typefaces are largely socially constructed, and Times New Roman’s origin story and design constraints don’t express these qualities."

Yes, formality and authority are both, quite literally, social constructs. There is NO "natural" or "universal" formality or even authority without human social input.

I would also argue that, though most users cannot distinguish between a serif and sans serif font, they DO understand the serif fonts connote formality. eg in high school they were told to submit their papers in a serif font, or where they read a court opinion they also read serif (even if not the same font).

Sure, the State Department could have selected a different serif font. But a reversion to what was previously used seems completely normal.

Secondarily, I do think Calibri looks far too casual for the State Department. Its what I would use if I were quickly printing out my notes...