Here is a Jewish Press article on growing up a curly redhead in bais yaakov.
It started when I was in first grade. I was an active kid with bright orange curls, and I’d never sit in one place long enough for my mother to even attempt to brush my hair. I was six years old, the youngest in my class, when my teacher called me to the front of the room. “This”, she informed the rest of the class, “is what a Bas Yisrael does NOT look like.” She then proceeded to braid my hair in front of everyone else as I did my best to hold back my tears.
To be fair, it is not policy in bais Yaakov to humiliate sloppy students. I can vouch for this, because I didn’t brush my hair between 3rd and 5th grade. I had curly hair and I had no clue how to take care of it.
So I didn’t.
I looked like an utter mess, but no teacher ever mentioned it.
That said, the emphasis on defining what a bas Yisroel looks like (hint: it’s a pretty narrow mold and you probably don’t fit) can be harmful, especially when taken to extremes like the teacher in this story.