I do not believe games and television need violence, both of these things can function and thrive without violence. If you'll recall original games did not contain violence, just think of Pong. Television has become more and more violent over the years, but if you'll check out shows like, I Love Lucy, you will see they lack violence.
Video games and television don't use violence as a way to gross out the audience, but as a way to enhance the media it is portraying. When there are video game violence, it is more exciting and it is alot more suspensful than watching shows where nothing happens and everything is child friendly.
Violent content is not a necessity in games, books, TV or movies. Sure, many good games, books, etc. have violent content, but many good ones also do not, my favourite example being Portal 2 (one of the two PG rated games by Valve), which I found was a masterpiece. Comedy movies and TV thrive without need for violence, and there's many non-fiction books out there that are interesting reads, despite a lack of violence.
As much as I love playing video games (regardless of violence level) and watching movies that have some minor violence in there, I can just as well enjoy a movie or video game without seeing violence. It's just a thing, but it is enjoyed by many and adds suspense, but it isn't needed.
Violence in video games only encourages children that violence is OK. But its NOT. Violence is something that happens in the world that shouldn't happen. Video games like that shouldn't exist because they are taking something inevitable and turning it into something fun, but its not fun. Its sad, depressing, unhealthy, and disgusting. So violence in video games is not needed.