I've noticed that even from playing Half-Life myself. The Armed Forces you simulations and games like Shogo, Quake, and other to desensitize soldiers so they can get used to killing real people in battle. There have been many arguments, namely in the US Congress, about these games. I have heard some of them, and I'll admit they do have a point. But it's where someone's First Amendment rights come in hand.
People can play what games they want, when they want to, and however long they want to.
I don't think so. Though two is more than zero, it's still not a whole lot. And it is, too strict if you ask me. If I could count the number of people that play Starcraft under the age of 17, the number would be astronomical. My parents and I pay no attention to the ratings set by the ESRB, Electronic Software Ratings Board.