Why? Why not have the people who do not want pornography content request such filters? Why not have these same people be the ones to request television censorship as well? I'm sure the rest of the population that is not living inside of a bubble is perfectly capable of deciding what they want to expose themselves to, not the Government.
Parents already have a large array of resources at their disposal; it is simply a matter of being competent enough to use them. Why should those who are not get a break at the expense of all else, though? They provide the essential means of access to various content (Games, music, movies, internet, ect.) and have only themselves to blame when innocent little Timmy starts killing hookers in Grand Theft Auto, listening to NWA, watches saw, and googles "naked."
There are two general types of parental controls:
1) Those that allow parents to filter what their child is exposed to and
2) Contraceptives that prevent the dolts of the world from becoming parents in the first place.