I know the score. Not every class is for everybody. That's why we have (or had) remedial, regular, and honors classes. Putting a student who is physically incapable of doing the work required in a particular class is a waste of resources. Putting a student who is mentally incapable of doing the work required in a particular class may be a waste of resources, and is certainly a dodgy proposition.
One of the responses my postings got is a pure textbook response that denies reality. Maybe it would work in a mainstream class but certainly not where, unlike an English Literature class, a mistake could be deadly.