The joke is that italic can also mean Italic, the ethnolonguistic group of those who spoke Italic languages and why Italy is named so.
The phrase "What has semantic HTML ever done for us?" is a riff on the quote "What have the Romans ever done for us?" from the movie Life of Brian, about a Jewish-Roman man mistaken for another Messiah.
No, that's not the joke, though for a brief split second, some moments after I wrote the comment, it occurred to me that the interpretation might arise.
Italic type is derived from a form of semi-cursive writing, and is entrenched in the European printing tradition. No punning with Italy intended.
So what does it mean if you have <i> around Chinese, or Devangari or what have you? Do you just apply shear to make the text slanted?
I suspect that it bothered some "woke" types that HTML contains Euro-centric typographical directives, so they have been repurposed to have some sort of, culturally neutral semantics that is more inclusive of the planet's diversity (pardon me if I'm not nailing the terminology here).
In short, <i> no longer belongs to whitey and his writing system.
While Italic type is a European thing, it is a very useful thing that does have some parallels in other scripts (Consider Rashi script for Hebrew, or how Japanese uses Katakana in a similar way). No need to get all 'anti-woke' about it: if it were the case that people had a problem with 'Italic type', the phrase 'oblique type' is right there for use.
Probably there are other useful bits of HTML/CSS for Asian languages. (right to left and/or vertical writing, anyone? I always wanted to fart around with pretty-printed Chinese poems and, like, calligraphy script fonts with procedurally generated jitter.)
