Actually, you still have a responsibility to not just the studio, but all his previous colleagues, even if he no longer works there to be careful with what he says as it could be taken the wrong way, or creative unnecessary headaches for the team. These are people, after all, they can see some shit and become demoralized from it because they're still working the game and still believe in what they're doing. To use a more extreme example, you can't work on a major AAA then leave and then reveal major plot points or details regarding features in the game. He didn't do these these things, but to say he has no responsibility to the studio is stretching. I think he's even currently at a major studio currently supporting 343 with Halo, which makes the initial dust up over his comments potentially worse.