One loud, misbehaving student can ruin the class for the other n-1. Idealists want to dream that there are no bad kids and it's all the fault of the patriarchy, white supremacy or worse. They may be correct, but work won't commence until everyone is sitting still.
Wouldn't it be productive and moral to find ways to help all 31, perhaps by putting misbehaving kids in special classrooms where they can receive specialized help?
If you don’t help that kid, the other 30 will spend their whole lives sharing a society with an adult who didn’t get help. That’s an unfair drain on their life too (increased crime, policing costs, etc).
Putting the disruptive kids in the same place as everyone else means the incentives are right to do something useful to help them.
From what I know of this sort of program, it seems to be a sincere attempt to help kids, not merely brush them off into a corner to forget about them. I don't know how often it's successful, but I think in that school district at least it's well motivated. From what I know of it, it seems like a much better system than allowing those kids to disrupt normal classrooms.
For these students who are deeply troubled, there must be healing before there can really be learning.