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.
Society has had laws in place to prevent children from viewing things they should not be (inappropriate movies, magazines, etc).
If nobody gives a fuck enough to affect business you can give the complete SAW series to 3 year olds and all the offended can do is yelp indignantly.