I never quite understood modern modding. Back in the day we knew it wasn't our game, we knew it belonged to the company and that modding was just for fun. Nobody was entitled enough to think they should make money off of, or be allowed to make a mod for a AAA game and the company would just be ok with that.
Basically, mods have always been against the rules. But we did it for fun. Then it became accepted by the developers, so people now feel entitled to mods and making money off mods you made in someone else's game.