The only people exhibiting any kind of shock over this are literally only leftists. No Republican here is showing any kind of shock or (?) disappointment.
Then I will be the first to do so. This was a bad joke and not funny. It has a large downside for teachers to be offended. I know my Mom would be offended if she heard this. And there is really no upside here. It wasn't some fatal disaster, but it was an unforced error.
Wouldn't anyone in education have stories about nasty stuff said in teachers lounges?
Sure, but if they do, they'll blame it on the person who said it rather than the fact that there is a the lounge. The teachers' union isn't this collection of union bosses descending on the school to weed out the trouble makers who dare to disagree with them. Most of the teachers are just regular people, regular coworkers. The typically elect representatives to the union who deal with the local bargaining issues and those representatives and the national organization couldn't care less about each others' views. You'd have to be paranoid to be terrified of sitting in a teachers' lounge because of political hazing; I mean I'm there is someone somewhere who is since there is someone somewhere who is practically anything.
Most teachers, even most politically persuadable teachers are going to read/listen to that and think Kasich just said they don't work hard enough.
I get that it was a joke and not something we ought to take seriously. But it was a stupid one.