They're doing it wrong.
These petitions should instead be banning consoles in general as an enabling technology to allow violence and crime into the household without an easy means of parental control- becase lets face it most parents have no clue how to enable that feature and most kids know how to bypass it completely.
No consoles = no violent immoral games to run on them.
Then all they have to do is properly lock down their PC so that the kid can't install software on it, and the parents have complete control and the ability to install only christian-approved brainwashing games like so many have done.
Oh and last night on Imgur, I saw a petition to ban the bible from being sold in stores for promoting violent crime, sexism, and incest. From the same line of thought that got GTA-V banned.