>Please read again. The second paragraph is precisely where I say that I have no problem believing that there might be ill effects. Our intuitions, however, are no replacement for scientific rigour.

They are not just out of the blue intuitions though, they are based on millennia of observations.

Empiricism is not just found in scientific labs.

I take your point, but this is not entirely true in this case. Cinema is less than 150 years old, and not long before that most people could not read. Mass media is a very recent phenomenon.

I am no expert in the history of social norms, but I don't think it's clear at all the protecting children from witnessing violence and sex is a human universal. I know of several cultures (e.g. Roman Empire) where it was normal to let children witness public executions or violent fights. Again -- I am not arguing that this is good, I am arguing that one should not make laws based on vague intuitions.

>I take your point, but this is not entirely true in this case. Cinema is less than 150 years old, and not long before that most people could not read.

Most people didn't make laws and force social norms either though. The "educated" classes that did had theater and other kinds of public shows (music, etc) since at least the time of Ancient Greece, and those did have certain codes about what is to be said and what shouldn't be said.

They also had special "adult" shows.

What millennia are you taking about? None of these cultural norms are that old. We still have people living in the jungle walking around with breasts exposed and nude beaches are quite popular on posts of Germany.

>None of these cultural norms are that old.

None of these cultural norms are that new either. Even back in ancient Greece and Rome there were rules about what constitutes public or on stage obscenity.

What "severe restrictions" are these? Having music and movies labeled as to their general themes/content? If in reference to the subject FBI investigation, do note that was over fifty years ago. Social standards have changed a lot since then.

Rating hurts funding and distribution channels for anything that is not bland, "family-friendly" content. Go to any modern cinema complex in the western world and you will see what I mean: dozens of rooms, no real choice.

You can argue that the internet solves this, but it's not really the case: for example consider the current YouTube "demonetization crisis" or the arbitrary rules imposed in walled gardens such as app stores. The bigger danger -- and there are many examples of this -- is that "think of the children" can be used by politicians to advance more nefarious censorship agendas. For example, trying to rate content that presents non-conventional ideas.

I don't think movie ratings are the cause of bland movies. The mass market has voted and superhero/transformer movies that cater to 15 year old boys are the biggest moneymakers. All the original programming has moved to TV, which is also subject to restrictions but is not the bland wasteland it used to be.