"No religion is true, but some religion, any religion, is politically necessary. Law and morality are insufficient for the large majority of men. Obedience to the law and to the morals are insufficient for making men happy. […]Law and morality are therefore in need of being supplemented by divine rewards and punishments."
I don't think it is possible, necessary or beneficial to control what a teenager views online. However, parents should teach their kids media literacy and skepticism so that they don't take everything they see and hear as necessarily true, and know how to evaluate the quality of information. Schools should teach that also, since many parents are unwilling and/or unable to teach that.
just like 'don't put your hand on a hot stove' proper firearms handling procedures how to behave towards the opposite sex, the internet is an easy thing to deal with. Raise yer kid properly, if some kid whacks themselves it's not the 'internets' fault.parenting and the internet
If a kid knows what is what you don't have to hover over his shoulder