It's all of them. It's Bruce, for being selfish and arrogant and marrying Kris and fathering two more children, when he already knew that he could not spend the rest of his life as a man.
This 2-night Kardashian "Bruce Special" is all Kris, when she saw what a positive response Bruce got after the Diane Sawyer interview, she wanted a piece of the pie.
It's Khloe, Kim and Kourtney for acting shocked and betrayed, even though they must have known prior to January that Bruce was full-on transitioning, since that's the reason Kris and Bruce divorced. (Except Kourtney, who can't act for shit, and delivered all her lines last night in an unsurprised monotone).