We've always had junk food, not comparable to digital pornography. But I do think we should tax it heavily and start to stigmatize people eating it like we do with smokers now.
The situation with porn today is more comparable to the mural, as porn is aggressively displayed and pushed wherever possible. It's not a private thing.
That is not true and the places that do in foreign countries that limit sizes of drink, etc does not stop or has helped to lower the obesity rate.
Smokers being regulated has not reduced the numbers for smokers, the reason smoking gone down is due to culture changing it's attitude about it. Enforcing regulation on anything does not stop jack shit unless the mindset behind it changes along with it.
It is the same process that you can find in people wondering why when you are fat if you staple your stomach you can still gain the weight back, it is because if your mentally have not changed your eating habits or behaviors you will find the means to do those habits regardless of cost or risk.
This is a proven mental effect and if society view on sex is very obsessive making some rules won't stop the consumption of it just like the 18+ shit does not stop children from viewing the content.
In fact probably promote it more due to if it is an addiction for some they will just invent ways to circumvent it, and for others causes reverse psychology making them even more curious then they would be before to look at it.
Sometimes the easiest solutions are the best ones of "you're 11 year old kid does not need a smartphone/any phone that accesses the internet," seriously if they need an emergency phone literally any phone with a charge can call 9/11.
You can buy a stupid track phone and you can have website blockers to prevent your kid while doing homework from accessing any site outside of the ones you approve of and watch them as they do it now.
We have so many means to monitor kids at this point you are literally incompetent as a parent if you want the government to regulate it at this point.