I care a lot about education, and I mean this with no hyperbole
I don't care about the sad backstory of why they can't function in a standard public school
special needs is the obvious one, they need their own system and resources, and trying to integrate them is a waste of everyone's time. They are not going to be "literally killed" but they don't belong in real school. There are planty of high-funcitoners who do just fine, this is not a one-drop policy or anything
The "dumb" kids are almost always in the middle block, and will reach a performant level if they are supported in school and at home. There would not be quotas, relegation, or any sort of danger of failing out of the system. (held back sure, but not washing out)
It's the population of kids who are unable to participate in the education process, being "disruptive" is a bad catch-all term, but if you are impeding the ability of the teacher to teach or of other students to learn, then you should be removed. And it's not a one strike policy or anything, you'd expect that with help from different teachers, school councilors, your parents, resource officers, etc. you should be able to participate in school just fine.
But at a certain point, yeah they should just be cut. tons of different ways to handle it at that point, but yes I would effectively write them off, and I'm ok with that. Education matters so fucking much, and I resent to completely that we stymie people who want or are able to learn to virtue signal that no child is being left behind