It hurts the kids who don't game the system. And it is illegal to not give a child any form of required education in Arizona, no need to keep using quotations.
For RBY's situation, it obviously played out okay for him as he's a successful wrestler, but having no education for an entire year is obviously not good in his formative years. Allowing him to do nothing besides go to wrestling practice and become addicted to video games, to the point where he is playing them until 5am every single night, is obviously not great for a kid. Explain to me how it is good for his development besides being stronger than his younger peers.