I always found it interesting how different books for teenagers were from movies considered appropriate for the same age group.
For example, the "Cherub" series by Robert Muchamore, which I greatly enjoyed as a kid, included crime, drug and alcohol use (even by kids), sex scenes, mentions of underage prostitution and human trafficking, and even a scene of an attempted rape on a minor. The much more popular "Hunger Games" series was a little bit less violent, but not by much. Nobody seemed to mind. Those books were clearly intended for teenagers, I'd say 12-16 year olds, and there were no disclaimers about what those books contained.
Even with TV, things aren't as obvious as they seem. Over here in Poland, very few parents care about age restrictions. Unlike English, we don't even have a word for "explicit content". Creating online accounts with fake dates of birth is pretty much normal. When I was in middle school, most people I knew watched porn with very few difficulties. Game stores don't have any obligations to restrict what kids can buy, it's not even clear if refusing a game sale based solely on the age of the buyer is legal[1]. When one game store refused to sell GTA5 to a kid, I heard about it on the news. When I compare people of my generation raised in Poland to our American peers, where explicit content is much more of a taboo, I see no noticeable effects of watching such content.
This has some disturbing censorship implications, how many real-life phenomena are filmmakers omitting to get just a little bit more viewers, just because of some well-intended laws that seem to have no actual positive effect on society?
[1] Polish https://bezprawnik.pl/sprzedaz-dziecku-gry-dla-doroslych/