Blaming porn is like blaming cheeseburger for obesity. While you're not wrong but it's hardly the root cause.
Same with porn and Pornhub. But it is the mental tobacco of our time.
You may want to check how early does porn (or sexualised images) exist. "our time" may turn out to be "since we discovered drawing".
We had obese people since at least the first settled societies. But it was nothing like today, both in how widespread and how extreme is has become.
Same with drugs. An opioid epidemic pushed by mega pharma is nothing like a shaman serving ayahuasca.
A nude cave painting or a figurine is nothing like thousands of hours of streaming porn. Barely related.
Hemp smoking, on the other hand, has been traced back to many prehistoric sites in asia and africa which would fit your description much better.