In this article from HR Zone, the writer discusses the legal aspects of the employer blaming the ship's captain, in public, for the disaster, before any investigation has taken place.
I guess it may be that in publicly chastising their employee in this way, the employer want to show the outside world that this is an individual problem, a 'bad apple', rather than a failure of procedure, organisation, training or other areas of employer responsibility. Even though it might put them in a poor legal position (at least in the UK), they probably thought that re-focusing attention on the hapless Captain Schettino was a good PR idea.