That's certainly part of it; here's the other part:
Far too many very wealthy people have invested far too much money into Rhee's makeover as a reformy celebrity. And far too many members of the credulous press have staked their own reputations on Rhee's image as a miracle worker.
She's the Citigroup of reforminess: Rhee is too big to fail. Everyone OK with that?
ADDING: I missed that one of Diane's commenters made just this point. Sorry, wgersen, I didn't mean to steal your metaphor!