Earlier quoted context omitted.
One thing "rich kid schools" do is filter out many students who are difficult to teach. Teaching and running a school is a lot easier if your goal does not involve teaching everyone who walks through your doors.
If that's the case, it seems like it would be a pretty easy problem to fix: allow schools to suspend/expel students who are repeatedly disruptive or violent in class. From a utilitarian perspective this would probably be a net win, in that whatever the disruptive students lost from being expelled would be more than made up for by what the students who actually wanted to learn gained from not having the disruptive stu…
Public schools have to service all of these students, until they graduate, drop out, or age out.