He should have put his hands up right away, and it would have been a learning point.
The dismissal is deserved for the lack of integrity after the event, not for the simple error.
To remove him from flying duty is a way to punish the lack of captaincy skills of an aviator. To dismiss him from the service is a way to punish his lack of respect for his fellow servicemen, and the culture that he was supposed to be part of.