Not sure the anger/surprise. They didn't take the map away from anyone, they just took it off public matchmaking rotation.
Which makes sense - only people that preordered have this map. There's no solution possible without fractioning the community far too much (as right now you can bet about 75%+ of players have that map.)
I'd guess it'll be included in the first map pack. Then there can be separate public matchmaking for people that buy that pack without splintering the community too much.
It's somewhat a sign of it being dumb to offer a multiplayer map as a preorder, but it isn't like they're rendering its value zilch.