I attended a private school in Jamaica 1st through 4th grade. My 2nd grade teacher did this. She sat students by social standing and perceived intelligence into A, B, and C groups. If you were rich and white or very, very smart, you were placed in the A group. If you were white and smart or rich and black, you were placed in the B group. The other kids, who were mostly there on scholarships, were in the C group. The A group kids could do no wrong. The B group was mostly ignored as long as we didn't act bad. The C group kids were often further humiliated and made fun of. She was smart though and would make sure she was observed by no one except us kids in the class. My mom volunteered at the school and the first time I saw her hit a kid for misspelling a word (scholarship kid who was severely dyslexic) I waited for recess and went to my mom. The headmistress was shocked that this could be happening at her school and, even though she didn't believe me at first, she knew my parents and had a great respect for them so she investigated. She caught the teacher hitting another student. The teacher was not a member of the religion of the school so was let go and was not able to get another job as Jamaica does not have the same laws about confidentiality and jobs are very scarce.
I say all this to say, those scars run deep. I still remember the tears of humiliation and the feeling I had watching this take place. It never happened to me personally and that was the only bad teacher I ever had but who knows how many kids she damaged. You must take a stand now. Humiliation does not encourage learning. Humiliation should only be used as a punishment, like breaking the neighbors window and having to ring the door bell and rake leaves to pay for it or making a child apologize for what they've done wrong. Not understanding a concept is not something a child should be punished for. If anything, the teacher should be forced to give a public apology to the students.