i also asked the question as to why perhaps they did not continue to gander (whom they were talking to on ATC with their mayday)
I'm not sure the call sign of who they were talking to initially matters, in the upper airspace they won't have been talking to anyone in Gander Tower or Approach, they would have been on one of the generic upper airspace frequencies labelled "Gander", which covers most of that part of the world.
As for airport choice the 380 is not my type but looking at some company documentation Gander and Goose are both given equal status for that fleet when it comes to suitability to diversion. If AF use similar then maybe given the visible damage to the engine and possibly unknown damage elsewhere the crew made the choice to divert to the "nearest suitable"...which would have been Goose. I wouldn't ignore that 1000 foot difference in runway length either....given the way the engine let go there could have been issues with flaps/slats that might have compromised the roll out.......
TBH despite the grumbles about ground handling given what the crew knew at the time I think it is difficult to argue with their choice of airport.