Games are growing as a storytelling medium. Since nobody is going to play a game where you sit and talk in a car for an extended period of time, they use what they have to tell the story and do it through action in titles of a type that big publishers know will sell.
If they're going to reach you, for better or worse they need to shock you with it. Especially for a game like "The Last of Us" they need to make the violence actually be awful or the game will miss its point, something they did with the last Rambo movie that worked surprisingly well. It's not unprecedented, it's just that people are too goddamn sensitive about video games and what people might think if someone enjoys playing that game.