It would, in this case, be pointless for someone to argue that the zone that the boat was in is uncharted or should be surprising to most navigators; and,
It would normal and prudent for one to flyover, zoom-in, zoom-out, whatever to look-out forward; and,
Routing isn't just about wind, sea state, precipitation, and current -- it's just as much about fixed things in the water (including those that are marked and unmarked in the day and night).

I'm not sure radar would have shown them much in this case. I assume there were no lights showing. If they saw lights but "assumed" that it was just some stationary fishing boats huddled together...

The archepelgo has some palm trees (not a lot) and very little vertical height. They would have been going about 18-20 knots. The radar (if they have it available) would have an 2-4 mile likely possible warning from where those objects might be on a good day with that really low lying stuff that was on that bit of sand on top of water.