My personal experience was that some teachers (Kirksville Jr High "Coach" Keith Jerome was one) actually let some bullying go on. Coach Jerome let some kids beat other kids that he didn't like. That would have been around 1974, so maybe in your Golden Age of individual justice and standing up for ourselves.

In general, I think that teachers do use bullies to extract revenge on students they wouldn't otherwise be able to punish. Same as we as a society let cops do extra-judicial killings and such.