The answer to your question is because sex is good, under the right circumstances.
Violence is bad. It's clear that violence is bad. When a teenager shoots people in a video game, they don't think "well, all right, this is fun, I should do this to real people." It is forever clear and well communicated that violence is bad.
Sex however, is good. However, it requires consent between two people to be good, otherwise it is bad. Worse than violence. This nuance is not apparent from watching a sex scene in a movie. I've heard of teens and children that saw sex scenes, and then proceeded to force themselves on others, because it's a good thing, right?
This problem however would be easily solves with some good sex ed. Actually, even decent sex ed would solve it. But USA, one of the biggest world powers shies away from sex ed like the plague, so, yeah.
Yes. Bad porn is bad. Bad sex made out to be good is bad.
I like your answer and want to add one thing. That in some cases violence is made out to be good. Cop stories, vigilante stories, every superhero flick ever highlights that violence is good when the cause and mentality is to "save" someone. Usually its men saving women and children. eyeroll Sometimes its mostly men and some highly sexualized eye candy saving "the world"
At one point in my life i refuses to watch my beloved superhero flicks because it was only about explosions and male egos. Lately its gotten * better * Marvel chatacters for instance are more complex, violence for daredevil for example is a necessary evil but stands by a code not to kill... etc... still lots of fighting-- and yes, i think it can influence children and even some adults.
Fair point. Violence for a good cause is definitely celebrated in some cultures.