Movies and Cds are different. A movie makes the majority of it's money at the cinema. By the time the movie come out on dvd, a profit has generally already been made, so it doesn't matter as much.
Bands go on tour and make more money that way then they would with a cd. Game retailers push used copies as soon as they become available, trying to take as much money from the devs as possible. Used games are game shop owners selling someone elses creation for their own profit without giving ANYTHING to the dev. That's the morally bankrupt part. And you support it.