I'm still not sure about the group that missed the boat, but why on earth would you book a private group if you're not a fit, young person in a third world country where private tours aren't used to cruises (and their "hard" time requirements)? I purely blame these passengers for making this decision, and I do not blame either NCL or the ship's captain. Despite all the negative posts, I'm pretty sure the captain waited as long as possible (it seems that the ship already departed late), but there's always a point of no return. And probably the passengers crossed that threshold.
Additionally: when I do my private tours (and I do plenty), I *ALWAYS* make sure to be back on-board at least 2 hours before 'all aboard'. These people did so many things wrong with the cherry on the cake their 'blame NCL media tour'.
I have cruised NCL once on my Honeymoon, absolutely loved NCL and don't consider myself pro/against NCL one way or another.