I guess one benefit of this approach is it costs nearly nothing. The better approach would be providing qualified tutors for free to struggling students, or to

I guess one benefit of this approach is it costs nearly nothing. The better approach would be providing qualified tutors for free to struggling students, or to make current math classes smaller, or to add TAs to existing classes. But all of that costs money. You could also argue that a more holistic approach could help. Things like better meals at schools, better transportation options to and from schools or a wider range of class times. Again, all expensive options compared to simply limiting options and forcing students into fewer buckets.