I could be mistaken but my interpretation is that "studying for your own good" is being contrasted with "studying so you don't fail". If you actually fail students, they'll have a second motivation beyond trusting some authority figure's advice. Namely consequences.

Coercion explains it perfectly. A lot of kids see no future because of the environment they live in, so they have exactly zero motivation to study

You are missing the point. Getting a certificate for all of the programs you passed and still graduating could completely change the course of a person’s life. Community college has certificates and associates degrees to let people start working when they reach a practical limit in their general education.