Dude. It's a sport. Anytime you get some guys togehter playing a game, it's gonna be laced with sexual jokes. A guy thinks of sex roughly 24 hrs a day. It only stands to reason that some of it is gonna show in other activities.

Golf would actually be a tamer sport for guys. You're only hearing it like you are because you've been playing a video game. Go play a real game a golf or any other sport, you'll hear plenty of dirty jokes by the end of the day.