Here's a compelling argument on The Objective Standard dealing with the concept of banning the sale of "violent" video games to children. In short: it's not government's responsibility to decide what intellectual materials are available to children, it's their parents' responsibility.
The money quote:
"Parents properly want to shield their children from the gratuitous violence so common in today's video games. But we must not allow power-hungry politicians to use that desire as a pretense for usurping the rights of parents to oversee the intellectual upbringing of their children."