We never had any prn when I was a kid, it simply didn't exist
Oh, but there was. Maybe you digged not your parent's underwear drawers, or cardboard boxes in the attic deeply enough, or had the right friends...
Agreed: It was by far less, and way harder to get, on VHS, or Betamax, or Super 8, or in form of magazines, black-and white fotos, or sketches, or painting... but there was porn. There always was.
Your example with porn is very good:
For centuries adults trying to prevent kids (and adults) from watching porn. But because of the internet today's kids have access to masses of free porn of any kind, I never thought those categories may even exist.
As a result the people grown up with the internet are by far way more educated and cleared up, and dealing way more mellow with sexuality than my own generation, more than my parents, more than my grandparents,...They are more mature about sexuality than former generations.
You may also find this in comparing cultures.
There are many cultures where human bodies, particulary women need to be (way) more covered than in the so called "free modern western civilizations." Point is: Depending on what people are used to, they get sexually aroused by seeing even small parts of a human body - or believe somebody else could.
When the Europeans got first contact with other cultures in Africa, America, or Asia they found people almost or completely naked - sure, why wear clothes when you don't need to, because it's hot, and you don't get a stiffy by just seeing a woman's naked breasts? That was the European's issue, not the one of those cultures used to this as being normal.
Now the "western civilizations" tell people from other cultures they shall wear less, having completely forgotten, or ignoring the fact, wearing short skirts, showing naked legs, not having women's hair covered,... was an even punishable no-go not fifty years ago. At the same time they don't allow anybody to wear less what they define as "correct". What an arrogance. Who do they think they are to define how much is too much, or too less.
What makes me really angry is when I see tourists showing naked breasts or drink alcohol in public in another country, where this is not unaccepted, while at the same time they come from a country themselves where exactly this same behaviour is prohibited and punished by law.
This is uppity, a combination of no respect, ignorance, and arrogance.
But you cannot teach this by prohibitions.
People need to be educated to respect others, dealing maturely with other's opinions, tolerate others, and not vice versa, just do whatever they like and require other's just have to tolerate that.
This cannot be done by laws.
Laws can only be a guideline, prevent the worst, or being misused to harrass, or empower ignorance.
But tolerance, and respect - love - comes from other sources: intelligence, knowledge and mature.