The question is whether naming the guy contributed anything to the story and was in the public interest, or whether it was a purely vindictive action by Gizmodo

The question is whether naming the guy contributed anything to the story and was in the public interest, or whether it was a purely vindictive action by Gizmodo. Considering the fact that the main story is the existence of the prototype and that it's authenticity has already been confirmed by Apple's response, I'd say it was the latter. Revealing the guy's identity added nothing to the story, unlike in your example where the lack of WMDs would be the story. Gizmodo have chosen to not only imperil this guy's current job with Apple but also his future career prospects. First by providing a market for stolen Apple secrets and being a willing buyer and publisher of the prototype and its details and second by splashing his name all over the internet. Count me amongst those who will boycott Gizmodo and all other Gawker sites from now on.