I read “Up the Down Staircase” at a formative age so I know what you mean. So often in life the realities are ignored for politically convenient fantasies and the person on the front lines gets nothing to work with and takes all the heat.
It may not be politically correct but schools need to be able to remove disruptive children from classes and work with them in a more structured environment with teachers who are able to deal with their issues. That is what’s fair to the children who want to learn and would give the disrupters a clear signal so they might choose to change their behavior.
You wouldn't have disruptive students if you were motivating them.
See how that works. I gave it up 17 years ago.