5t, the only part about your post which is true is that mir doesn’t acknowledge yom ha’atzmaut, same as any other non-european Hebrew nationalist yeshiva. plenty of the talmidim, especially in the last few years, speak Hebrew, because they’re sefardi and their families came from Israel.
Most rebbein in most yeshivos teach tha5 ivrit is no good. Most offer hebrew as a regents test; I’m pretty sure mir does too.
The shiurim are all in English. I have no idea where you got the jdea that they expect you to speak Yiddish. Mir, like every other Brooklyn Yeshiva, translates chumash and mishnayos into Yiddish, but it’s downplayed as time goes on.
I spent some time there. Your post sounds like something out of the NYT.