You've mentioned two extremes - 7 year olds should be completely supervised, 14/15 year olds can make their own decisions.

Do you think there ages between 7 and 14 when kids should be allowed to watch videos unsupervised and kids should have some form of filtering they don't see inappropriate content? If so, who will provide that filtering? You probably can because you post to HN but not every parent will have that skillset