Journal: Why can't there be unrated video games?

In midst of all the controversy from Manhunt 2's rating, why can't we have games without ratings be released into the public? Movies are allowed to be sold on DVD without ratings from the MPAA. Nintendo and Microsoft and maybe even Sony say they won't allow AO games to be sold, since the line has to be drawn somewhere. So if the game wasn't rated at all, would it be sold? Probably, because there is an audience that demands it. But I'm probably missing the bigger image, and there's must be a very