Someone on the ship's bridge had to see the fishing boat and that information should have been relayed. If not, then the competency of the crews hired by the cruise lines really needs to be evaluated. What are they doing up there if the passengers are seeing things and the bridge crew is not? I may have answered my own question on competency.
Actually, it is quite possible that the the bridge crew didn't see the boat, or if they saw it they may not have realized it was in distress. It is a really big ocean, and this was a rather small (9 meter) fishing boat. In any kind of waves, a small boat is partially (or even completely) hidden from view when down in the troughs.
Understand that at sea the bridge crew is mostly concerned with not colliding with other large vessels. That means they are concentrating their view forward, not off to the sides. Small boats don't always show up that well on radar, and at sea ships probably have their radar set on longer ranges, to give early warning of other big ships in the area. Or they may have seen the fishing boat, realized they were not on a collision course, and then paid it no further mind. If it was somewhat far off, they might not see someone
"...waving a red T-shirt, and ...waving a bright orange life jacket over his head...” if they didn't take the time to study it carefully. Note that the
"...birders..... spotted the drifting fishing vessel with powerful binoculars..." If you spend any time at all reading about shipwrecked sailors you will find many, many accounts of ships sailing right by and not seeing survivors in rafts or lifeboats. It has happened many times before. People who have not spent much time at sea have no idea of how tiny a small boat can seem when viewed against the immensity of the ocean.
I am reminded of when I was in grad school, I made several voyages on oceanographic ships. Once we were trying to find an instrument we had set out a day or two before. It was a relatively small peice of gear (much smaller than a skiff), but had a mast on top with a flag. It also had a radio homing beacon, so knew we were very close, and even knew which direction to look. Even so, with all hands looking intently, it still took quite an effort to find the darn thing.
I don't find it at all surprising that the bridge crew either didn't see it, or saw it but didn't realize it was in distress. The real issue was that when the birders saw it, the information that it was there and in distress was not relayed effectively to the bridge.