Ultimately it’s appropriately paced education. Some people need accelerated education and some need decelerated education, and it might vary between subjects for an individual. Not having opportunities at either end of the spectrum is bad for the student because they’re can be left behind or not challenged enough.

Very few people take issue with providing resources to someone falling behind. On the other hand, enough people take issue with letting someone get ahead that it has become a political issue, and has lead to regressive educational policy.