Porn already is controleld much more than it ever has been in the history of the world.
Yes “the Victorians” or “the Puritans” took a dim view of erotic material more than we do, but access to materials just needed you to walk to the bad part of town, where you’d engage a (likely trafficked, likely underaged) sex worker.
I agree that porn can, in some circumstances, under some conditions, to certain demographics, be both a negative thing (and in other ways a positive).
However, you’re never going to rid the world of horniness without chemically castrating the entire population of the world, and then there might be paraphilias that evolve even if you do.
So it’s very much a case of what is freedom of speech, literature, art. Is The Birth of Venus porn? Could you make an argument for ancient portraits of babies with their weewee out being child porn? What about crudely drawn murals from antiquity? What about bathroom poetry? What about people having sex on a mountain (you know like we all used to do 100,000 years ago). Is Game of Thrones porn? Is 1984 by George Orwell porn? Is 120 Days of Sodom, which contains a LOT of disgusting sex and child rape, but was written to criticize/expose the aristocracy, not intended to arouse people, porn? What about Chuck Tingle, who writes to satirise porn not truly arouse?
if all of this stuff is foisted on us by existing should anything be allowed to exist?
I’m also not saying that porn is inherently good, nor am I saying nothing should be banned, but I am saying you haven’t adequately defined which porn should be banned, and without doing so you end up with a Diagenes’ plucked chicken: behold! a pornographic image!