So the idea that he gets to do that and then decides to leave Starfleet becuase they want to reassign him (which is better than what I would which would have been to court martial his ass) makes it seem like he's trying to weasel his way out of facing the consequences of his actions, not to mention that fact that keeping the Challenger which sounds is kind of shady since a decent chunk of it is made from the remains of a trashed Starfleet starship kind of makes the guy look like a major asshole.
In Carey's defense, we don't know how she would have executed this idea.
On the other hand, Carey's last major creation before Keller, Red Sector
's Eric Stiles, was
a self-centered asshole.
All I can do is throw my hands up in the air and shrug. We really don't know.