Looks like they had the very hard landing (the reason being unknown) most of it on the right main landing gear, which suffered great damage along with the engine.
They went around (most probably because they followed SOP or because they didn't think they would safely stop on the runway)
During the missed approach the extent of the damage must not have been apparent, or they would have returned immediately.
Once they learned of the status of the airplane (reports by cabin crew, ECAM, etc…) they decide to land on a longer runway and prepare for the worst, that is, to prepare for evacuation.
A man makes decisions with the info he has available. If he has time, he should use it to get to the best possible decision. When he learns he doesn't have the time, he will land with no delay. They did this, so it was ok, unless the first hard landing was a handling error, in which case they have a not so good score