What exactly have they done that is "evil"? Is earning a profit evil, in your opinion? Please tell me. I know we aren't allowed to discuss politics on these forums, but I'm not going to let that get away. It's probably best to lock this thread before this turns into a large "political" discussion.
From a video game perspective; resellers take money away from Publishers and Developers. You know, the people who develop and publish the games you play.
Scenario A: You buy a brand new game at a store. Obsidian and gamesas gets chunk of that money, and get a +1 in their "bought this game" column. If a lot of people buy it, they get lots of money and can make more games like it.
Scenario B: You buy a used game at GameStop. Obsidian and gamesas get zero money, and have no way to track the sale. GameStop keeps 100% of the money so they can ... Uh .. make the store prettier? And when you're done, you'll probably give it back to GS for $5 store credit, and they'll sell the exact same copy again for another $20-30.
DLC circumvents the stores. Not only preventing resellers from selling it used, but also makes less middle-men on new games. The FO3 DLC wasn't sold retail until GotY edition, as far as I know. And even better, DLC can help give an accurate count of people actively playing a game. If you buy a game and stop playing it a week later, you're probably not getting the DLC. If you buy it used, and love it, you probably will buy DLC.
Hope that was unpolitical enough