Do you actually believe this nonsense? Caserio could have fired Kelly himself. And if Culley didn't like it, he could've quit. And saved the McNairs $17 million.
I know there's a reason Caserio fired him and he said philosophical differences. I could definitely see Caserio wanting to move on from Culley after he said Kelly definitely would be back and Caserio said, I tell you what, neither of y'all will be back.
This doesn't even take into account Calhoun may have wanted to get rid of Culley. I mean, if Calhoun is going to hire HCs then I wouldn't put it past Calhoun to fire HCs.
Just remember nothing has changed down on Kirby. The only thing that may change is the guy picking the players looks like he's better at it than previous GM's.