Autistic son's geometry teacher

I need to know if I'm the person in the wrong. My son is 15 and has autism, ADHD, and Dyslexia. He is not a big fan of math. He does really well in band, English, and social studies. He spends part of his day in the SPED classroom. They had a text in Geometry last week. My son did really bad. He got a 9%. I love teachers. If it wasn't for teachers my son wouldn't have improved the way he has. Many of my friends are teachers. But there is a way a teacher should handle things and I do not appreciate how she did it. She decided the best way to encourage students to do better is to call students to get their tests and announce their grades, best to worst. And my son was last. She made him cry. I was furious and had a meeting with the principal over it. From what I have heard other teachers in the school agree it's wrong to do that. Am I right for being upset.