Sure they are. Managing Editor is strictly a title related to the specific broadcast. If he was VP of NBC News AND Managing Editor, you might have a point. But he's just in charge of his show. There are lots of other higher managers running around that could have been alerted.
But truthfully, there is a friendly way for a producer to alert a talent, regardless for his clout and title, that he's making a factual mistake. These producers are in the union, and can't be fired for doing their job.
Having said that, it's likely that this was covered early in the investigation.
Office politics is viscous in network news operations. And senior management listens to big-foot air talent, not line producers. Producers have a guild but it is not a collective bargaining unit.