It's just that I prefer playing against people that make rational judgments and having better information about the state of the game encourages players to make more of those. There's nothing altruistic about it.
If it means that someone will attack the dominant player in a game rather than one of the weaker players, if it means that someone will attack the player who's just missed a turn to cut down his missed turn bonus, if it means that someone will conquer two countries from a player to reduce his armies due next turn, then it will have been worth it to me. I benefit when players behave rationally because I can predict better what will happen in the game.
