Share the burden.
Down syndrome, self contained, EBD, etc.....
Very few private schools seek out these students - in fact, they avoid them like the plague.
The few private institutions that do serve this population are ALWAYS non-profit.
Give public schools the freedom to give choice and vouchers to the students who they are not adequately able to serve.
Then insist that private schools must accept these students.
If a student is a total failure and/or discipline problem in the public school system, let's give private schools the chance to show how it should be done.