The issue here is pretty fair, as I see it.
Double Fine gets advanced some $20 million by Vivendi to make a game. They're doing so, when Vivendi has to make a difficult decision--Vivendi hooks up with Activision, and Activision says, "Yeah, this looks like a dude. We're dropping it." Vivendi seems okay with that, so Double Fine's project gets dropped.
Then Double Fine decides to take this project, which was created using borrowed money, and just ship it elsewhere. Problem: It's possible, just as Kotick says, that the rights were not theirs to sell. We'd need to see into the terms of that advance, but once you start working with a publisher, you've pretty much signing over SOMETHING in terms of rights. You can't just take the work that they paid for (you may have done the work, but they paid the bill) and go somewhere else without permission... or at least without paying back what you were lent.
It's one thing if they just gave up on the project and called it a loss. It's another thing if the studio decides to take what you paid for, go somewhere else, and sell it behind your back without so much as a tip. Activision is a publisher, not a charity.
Depending on the terms (to which we are not privy), this is a fair appraisal of the situation.