Confusing

Is thus an American thing? Were forced to write cursive...

Yeah, your not supposed to use cursive in math. Mathematical equations have set constants that are annotated by specific letters and symbols. If you write them in cursive, it can become a different letter/symbol, changing the constant and make the equation fail.
This is a hacky, bad teacher teaching bad habits.

I write in cursive on everything like I physically can't stop myself and all my teachers hate me because of it