“I am very disappointed that other parents did not descend upon that school en masse.”
It is disappointing, but parents are probably fearful that if they speak up, the teachers will take it out on their child.
Some parents may be afraid to speak up. Their fear is understandable.
But, most parents are sheep. They follow the crowd, believe what they’re told to believe, do what they’re told to do, and don’t ask questions.
Time to pull the children out of danger.