Government schools get no right to choose whom they educate, Private schools do.
Education will not improve until parents send better behaved kids to school. Most people never consider that juvenile offenders are usually required to attend public school as a condition of parole/deferred sentence. That includes murderers.
A real concern is of course that the Charter schools will siphon off the cream of the crop and leave the dregs in public school.
If you had read my entire comment I said that government services don’t have the right to discriminate. I agree that the parents have a lot of blame, but that’s another problem.