Well, I am a well-behaved person in real life, so I look to games as a way of doing things I would never be doing in real life. Why is it fun to kill people in GTA or torture a family in The Sims? Because it is something you can't do in real life and it is just entertaining to experience a glimpse of a different reality.
Of course we could easily have games, in which you have to go onto tinder, get rejected 172 times before finding a girl willing to meet you, then get turned down, go back to tinder and try another 102 attempts to find a new girl, who turns out to not be the Arianna Grande twin that her profile picture suggested, but something closer to Hillary Clinton and run away from her as fast as possible, cycle through another 45.7 girls on tinder, until you find another who is interested in you and willing to hook up with you, and you end up marrying her, find out she has been cheating on you with your brother who has a bigger dick than you, and that she was only dating you for your money, lose half your shit in the divorce and then resort to spend the rest of game drinking beer and pitying yourself. (Read this sentence in a single breath, I dare ya!)
OR
You could have a game where you are surrounded by smoking hot girls and you end up fucking all of them into a sweaty pile of flesh, using your dick - which is the size of your average anaconda - because you you dont care about their feelings and blackmailed them with their naked photos or held a gun to their head, or whatever reason.
One of these games sounds pretty damn boring. The other sounds like a fun trip away from my usual reality. Guess which one I will pick?
Basically, I almost always look for games, which allows me to be an asshole to women, because it is something i would never do in real life and I find it fun to just use women as slaves and not giving a shit about their precious feelings.
If you still don't understand my point, try the following: Upload a 10 minute video to Youtube of you sitting in your kitchen, eating breakfast, like a normal person. Next upload a video where you walk up to Miley Cyrus or Emma Watson (any celebrity, male or female) and punch them in the face. Now compare which video gets the most views.
People are usually looking for an escape from their daily life in games, and that is a big reason as to why so many of these adult games have assholes in them.