Pretty sure it's just anti-American signalling/globalist cultural imperialism. Asian/8601 date format makes a lot more "logical" sense, but nothing beats what you grew up using, at least for me, in a non-technical context.
But I am one of Those People who goes around $WORK's internal wiki (which has users in the USA and GB) telling people off for failing to use 8601 in their meeting minutes, so perhaps take with a pinch of salt.
(edit) I'm perfectly fine using 8601 in technical contexts, or anywhere really, but describing American cultural practices as "insane" and "bizarre" is exactly what I'm talking about.