Firstly, this scenario is not rare. Probably less common than 50 years ago, but not rare either.
Secondly, there are other forms of abuse that are relatively commonplace. The use of shame as a tool for discipline is rampant. This can include name calling, saying embarrassing things to a student, punishing a child publicly, and forcing kids to embarrass themselves in front of classmates or other kids. The trained rebbe neither does these things nor feels a need to stoop to this. But the overwhelming majority of our mechanchim have never participated in a program to train them to manage a classroom, build a curriculum, or establish constructive relationships with talmidim. The situation today is much improved over past years, but we are still far from making our yeshivos emotionally safe for our children.
This comment, rash as it is, might throw a different thrust to this thread.