We are not allowed to kick students out of school anymore. Each student has a dollar sign on their head rather than funding the schools by children in an attendance area. The schools now only get paid per pupil, per day each child is in school.

Also since 1975, special education has exploded. Sort of corresponds to the rise of vaccinations. We no langer sends students to special schools for their disabilities, instead, every child is entitled to go to their nearest home campus.
Having special ed children is not so much the problem as good special education programs tend to raise scores of lower-achieving students that don't qualify for special education.

The problem is funding these programs. It is very costly. It means every child in school is very important to run the school as creative financing is used to displace money to support student services.

So bad behavior is tolerated, and teachers are trained and condition that they are totally responsible for what happens in the classroom. one bad apple can spoil a barrel and make it hard for a teacher to teach and govern a class. the bad behavior does rub off on other kids and they push as much as they can to see what they can get away with.

At the same time, the administrators really don't want to be bothered with disciplinary actions. There needs to be a clear and consistent paper trail and interventions. Getting teachers trained and motivated to follow those procedures is nearly impossible with classrooms full of children feeding on one another's behavior. Because the teacher needs to divert their attention to document, document, document.

After all that documentation, meeting meetings, meetings. More documentation, before the child is diagnosed and placed in a behavior intervention class. Then the student only to return to the regular classroom after a short period of time to deal with specific behaviors that always return. In the meantime, everyone else in the regular learning environment has been poisoned and new norms persist.

Administrators are terrified by law suites and also don't want to lose their cushy positions. Working back in the classroom is a slap in the face and something no one with experience and training in school administration wants.

So, are system is all about enchanting and entertaining children trying to coax them into wanting to learn. If the children are not enchanted, then a teacher is not teaching. Teachers have hardly any budget and little creativity with highly scripted, goofy, material and no help to put together a high production quality learning environment in which children will not get bored. Never mind because of technology that students now have the average attention span of 3 seconds before they turn off and seek more stimulation. So teachers do their best to cover material quickly and revisit it learned well or not.

It is also increasingly rare for parents to take the teacher's side as well. It is all about what did you do or not do as a teacher to upset their child. And, admin backs the parents, instead of doing their job and advocating for the teachers. So teachers, tend to pass students along not making anyways waves in choosing not to discipline students. It will all come back to bite them as ineffective teachers anyways if they raise a stink or have high standards. Admin does not want to deal with it either. Neither do the parents or the students. So teachers have become little more than glorified babysitters. They try to save the ones they can and placate survive the rest. Picking your students is not an option.