When he was cornered at the public meeting on Thursday 26th February the captain said, "I understand everything. I understand that your cruise has been ruined'. This comment was recorded at the time by a passenger.
Later, he stoutly maintained that, as a Sicilian, he was a man of honour *
Chairmen and Chief Executives often resign their position in recognition of the failures that have taken place under their leadership, even if these were the direct, personal responsibility of subordinates. It's hard to see why the man most closely associated with Costa's huge failure to offer anything like the advertised cruise shouldn't follow their example and resign his command.
As a man of honour, of course.
* Like Brutus, perhaps? Julius Caesar, Act III Scene II