The sheer amount of art assets that have gone into these expansions can't be produced for free.
Leaving aside arguments about the gameplay provided (some liked it, some didn't), there has to be a funding model for this.
Maybe the model doesn't give you what you're looking for out of this game, and that's fair - you can just move on to a game you do enjoy.
But for some of us, the additional zones, weapons, gear, raids, encounters, enemies, vehicles, quests, mechanics, maps and modes that come with the paid DLC are worth the money.
I don't think it's "nonsense", I think it's fair value for the time I spend, and the enjoyment I get, out of the game.