Correct me if I'm wrong but the extent of the "hacking" was exploiting the fact that many people had not reset their voicemail pin from the default (making their voicemails accessible to anyone who'd spent 5 minutes reading a phone manual).
No skill involved, not even much guile. Just exploiting a weakness to see what dirt they could scrape out.
YABU.... 'Hacking' just means illegally gaining access to something that is password protected. If people want to think of hackers' criminal activities as somehow intelligent and admirable, I think that's their problem.