Dunno, I used to be a teacher and it'd be very obvious the reason the kid doesn't know is because they weren't listening. Then instead of admitting they didn't know because they're not listening, they just started to spout total garbage.

All my students knew it was fine to say "I don't know", the purpose of a lesson is to learn. If you already know, you might as well play outside.

But not listening, then spouting bullshit, would have annoyed me. If you don't listen, there's no point you being here, so get out. Which is what I would have said.

I agree there's no need to shout at the kid, but teachers are human too, and I can understand how frustrating it is, because I've been there.