Never understood why the teacher punished the whole class for the antics of one kid. The teacher knew who did it and if she did not it’s not like the other kids would not sing like a bird to keep from being punished at that age. I know we did.
I ran into this decades ago, when my now adult kids were in middle and high school. 9th grade teacher was an ah*le, tried to fail the entire class, even though it was mostly his fault. My daughter was in a journalism class, with a mix of students from 9th through 12th grade. They were responsible for putting together the yearbook, and the teacher kept changing the requirements and had problems meeting the publisher timelines. My daughter was a straight-A student. When the gay teacher (yeah he was flaming gay) gave everyone a D or F grade, I wrote up a legal complaint and requested a meeting with the principal and teacher. Principal backed up me and my wife, reversed our daughters grade and the teacher was removed from teaching the class from then on. Victory! You have to speak up for your children against bullying teachers who are also incompetent to teach. My daughter later went on to becoming a journalist and editor for magazines and is doing extremely well.