The captain should have at least called in for a smaller, more capable boat and/or helicopter. This case makes me wonder how a captain of this cruise line would treat a "man overboard". The rest of what I have to say is probably a minority opinion...
It's seems entirely impractical and uber-dangerous for a huge cruise ship to stop every time it appears a small vessel may need a rescue in the open seas. It seems to me that a large cruise ship would be stopping maybe 3 times every cruise. By the way, I have to wonder how many of these cases happen where a cruise ship keeps going. This case just happens to have a survivor who can report what happened.
The point about the pirates is valid. There are some really evil monsters out there that only happen to have DNA similar to human beings. The captain is entirely responsible if the people in the small vessel board the ship, turn out to be pirates, and kill some passengers. The alternative is for the captain just keep going, as he did here, and have some people say he's a really bad person.
By the way, pirates could easily learn the international distress signal. So, that'a a non-starter.
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If you're reading this, it's too late.