I stand by my assertion that they would not have hit the island had they been equipped with NVG.
When you do a night letdown over water wearing NVG you are mentally prepared for the visual environment - when you are relying on radar and AFCS procedures only, then you are in a different (almost IFR) mindset.
Having used the AFCS to get down to low level, they would have been using NVG as primary collision avoidance and FLIR and radar as secondary.
They would have seen the island in that case.