This is exactly the case. This is something Congress can do that might possibly redeem their abysmal approval rating in the public. For the vast majority out there which no nothing about video games, this is a win.
We know it's a loss and a colossal one. How do we convince people about it? This is no more than the rating system with movies. Back in the day when a movie was rated R kids didn't see it for many reasons:
1) Movies theaters and movie ushers didn't sell tickets to underage kids
2) There was a stigma to even going IN to see an R rated film
3) Parents could make the individual decision when it came out on cable, TV, VHS, Beta, RCA Video Disc etc.
This is the same thing. Parents, if you see a game rating above your child's age - don't buy it! or if you really feel that little Johnny can handle Nun Slashers Effect 3 for the Sony EyeStation then go ahead, but don't blame the video game industry when your son gets busted for assault and ends up living with you until he's 45!
Personally, I'm going to contact my representatives and also call and warn my Congressmen that this bill is a bad idea for these specific reasons. It only takes usually 25 calls per office to make a particular view on an issue stand out. If even part of Slashdot's collective might calls or writes in then this bill can be removed and we can move on with more important issues. Remember to also calmly include that you are a voting constituent and if you are of their party then mention that too.