This article suggests that machine learning and collaborative filtering are incapable of producing healthy recommendations. I beg to differ, the New York Times may not like the result but they work for the vast majority of users on any service with too much content to manually curate.
The parents are the most well placed to know at an individual level. But responsibility is a cop out, if you are just dropping it on someone.
Granted, I agree it is a hard problem. Not even sure it is solvable. :(