For that matter, I'd have zero issue with more classroom time spent on art, music, or other subjects of that type. But the fixation on an aesthetically pleasing copperplate writing style has about the same justification as universally teaching ancient Greek because it's part of a traditional Western upper class education.

> part of a traditional Western upper class education

Such reasons have actually started to become a bit compelling to me, and might lead me to learn Greek, though I might do Latin first. It places you next to others who have learnt the same things through the centuries. Joining the same learning tradition grounds you in a common language and a common literature. It helps you understand intellectual conversations from today and from past generations. So I imagine, at least; I'm still just an ἰδιώτης.

You are assuming that cursive is "useless" and lacks "some non-zero eventual utility". Practicing fine motor control seems like an excellent use of time to me.

I am not assuming. The article contains evidence that it is useless vis a vis block or custom handwriting.