Gods, I hate that. I get that kids are essentially sociopaths, but it still sucks. I was in the AP/advanced English classes, and a lot of the kids through the years were total dicks about that with other kids. It's one thing to give someone the formal pronunciation, but don't mock them.

I'm sorry people were jerks to you.

What's worse is that your pronunciation is one of the more common variants among irish immigrant descendants in my area, just with an sh at the end instead of just an s. Weird mountain people lol, they know a smattering of Irish loaner words, but they've changed over the years.