I understand what you and others with this argument saying. It seems unfair, but if you don't "punish" the loser all you're doing is delaying the inevitable. If you let the loser into the playoffs, they'll have a tough road game, and if they win they'll be right back where they were on championship game weekend - playing a great team on a neutral field - except this time, if you lose you go home.
I don't think of it as a punishment or an "extra game". It's an opportunity to avoid a road game in the playoffs. If I'm Alabama, Ole Miss, or Tennessee - I'm begging for a shot at Texas on a neutral field. Win and you avoid a road trip to Ohio State, Miami, Oregon, etc and rest up during round 1. That's well worth the risk, IMO.
You can't avoid tough games on the way to a natty... if you're a 2-loss team at the end of the regular season you're either going to play in a conference championship game where if you lose you MIGHT go home or you're going to play a road playoff game where if you lose you are DEFINITELY going home. I'm taking the conference championship game every time.