The identity of a subject is perhaps the single most important piece of information possible to contain in a news article. It certainly shouldn't be left out when known, merely because the subject prefers it not be stated.

If there's a clear, consistent, and disclosed reason for not revealing the subject's identity, that's one thing. But you're suggesting journalists, or worse subjects themselves, should decide whether their identity has journalistic value?

Furthermore, I disagree with characterizing the use of one's real name as a "slip up". It seems like pretty clear evidence that the author did not seriously care about their anonymity.