A good director/writer knows when there's a need for explain something and when is not.
Ignoring stuff might serve for a purpose; for example, the less they talk about X-Men: The Last Stand, specially Xavier's death, the better, since people didn't like or cared much about that movie. Those themes were only ignored or left in the background.
Singer didn't have to explain much on that for their movie to work and it was still much loved. There's no need for over-explaining everything to death. The only true need for the movie is to be enjoyable and good by its own, everything else is secondary.