Where have you been the last 50+ years? Porn has been and continues to be under constant attack by society. In the United States, even the First Amendment hasn't been as solid a defense as its wording would make it seem for pornographic works, and some states still have laws on the books banning "obscene devices" (though admittedly sex toys aren't speech)
People don't like others having sex, don't like knowing about it (unless they themselves are horny and want to see it, but heaven forbid anyone else be allowed the same privilege, which is the main reason you see so many anti-gay male politicians being caught in compromising positions with other men), and want to control everything about it.
There are two evolutionary reasons for this.
The first is pregnancy; and the difference between societies that have evolved without access to effective natural birth control and ones that have is as stark as you'd expect it to be.
The second is scarcity, which is related to the first thing (i.e. people weigh sex against major negative consequences if having sex can have major consequences), but can be slightly abated by a massive distribution network of pictures and videos of sex (while not the same thing, unlike physical hunger sexual appetite can be satisfied by the equivalent of simply looking at a picture of a tasty meal for a few minutes).
Modern society has only had 50 years with technology that does those two things reliably. Society at large just hasn't had enough time with these factors in play to loosen up, but the cracks are beginning to show.