I know quite a few people who don't like how pervasive sex has become in literature and movies and TV and...well, life in general. It's too in-their-face. It shows too much. Why can't it all just be left up to the imagination?
But, personally, I like it. It feels more honest this way. More and more authors and producers and creators are including this aspect in their media because you just can't not include it anymore.
Every single person on this planet owes their life to it. They're very existence is proof that sex happened. Almost everyone is going to experience it at least once in their lifetime. Most people are going to experience it a lot in their lifetime. It's an act that gives people pleasure and connection and intimacy and joy.
It's an important part of life and, if stories tell characters' lives, how do you justify excluding or even glazing over this? Especially in stories that depict and centralize around romance and intimate relationships! It's part of the story. Why would you leave it out?
Why is it seen as so obscene?