This open letter to King is worth reading. While I don't think it's really a bad thing to maintain copyright, or purchase the rights to other material, at the end of the day what do you do with a strategy designed to use those systems to destroy someone else's game?
Might be of interest to those interested in copyright in general. CandySwipe was copyrighted, but through "inventive" action King was able to effectively null that claim after CandySwipe stood in the way of their own copyright claim to Candy Crush Saga.
Just another blip in the long war between game makers King and people with taste and decency.