If those excluded kids are just moved from selective charter schools to non-selective public schools then, by the same argument, they'll be reducing the outcome

If those excluded kids are just moved from selective charter schools to non-selective public schools then, by the same argument, they'll be reducing the outcomes of the non-disruptive kids who don't have parents involved enough to take advantage of the system. So unless these charter schools have a side business selling Soylent Green made from disruptive pupils and those with learning disabilities, they're not actually improving overall results.