I wasn't even aware it came from latin, but that makes perfect sense. But it's weird how it was considered bad up until this late in history, but it wasn't until 1938 that someone patented the smudge-free ballpoint pen. I imagine that smudging with your left hand as you wrote must've been very irritating and wasteful for hundreds of years, and thus it became a sadistic ritual to "right wrongs".
Here in Denmark we called that type of schooling "sorte skole" (black school, an expression from the mid 1500s, where schools were run by religious institutions, so perhaps it's a reference to their clothing?), and it didn't matter if you understood the subject or not, you just had to memorize it and do things correctly, even writing with ones right hand.

Dictionary lookup on google translate