If you had read the article, you would know the answer to this question.

Calibri is a font designed to be easier to read on screens, which is where documents are primarily read in 2025. Switching to using Calibri as the default was a meaningful change that provided improved accessibility at literally no cost to anyone.

Switching back to Times New Roman, a serif font that is provably more difficult to read on screens is yet another act of performative cruelty by this administration who seemingly operates with "the cruelty is the point" as one of its core tenets.