This is only an anecdote, and one example, but watching it made me realize how important it is to at least frame your children's experiences and to put them in context. Okay:
There was a guy I knew about 7 years ago who had a kid that was 7 when I met him and 10 when we parted ways. Every day, when he got home from school he would turn on the PS2 and play GTA 3 or Vice City. The father told me that the kid knew it wasn't real, and that it wasn't anything to worry about. This part is the "correlation is not causation" part, but each year of school he was in more fights and altercations than the year before. It didn't hit me until about a month his 10th birthday. The three of us were in the backyard watching skydivers come down (airport very close). The kid says, verbatim, "Dad, I really wish I had a sniper rifle so I could shoot that guy down, and hear the 'BAM' when he hit the ground, then we could use a flamethrower on his body to make sure he was dead". Dad says "you don't do that son, it isn't right" and nothing else.
Now that doesn't prove anything, but it struck me that parents definitely need to maximize the time they spend introducing the various concepts of life and humanity, including media, lest they not even understand the finality of death at age 10 or how heinously wrong murder is.
That said, I don't personally feel it's the governments place to do anything about that, and I'm sure it's parents who have their TV as full-time babysitters who support this kind of thing. Don't have kids if you can't even be arsed to introduce them to the world properly.