The hypocrisy isn't with the sub. Extensive rescue efforts always happen with oddball accidents and disappearances. Any sub or ship disappearing while exploring the Titanic would get the same attention.
The hypocrisy is with handling refugees in general. Just like with the local homeless, nobody simply knows what to do with them, everyone likes to pretend they kinda care but also want the problem to go away, and nobody wants to have them in their own back yard.
Well, unless it's Ukrainians with "blond hair and blue eyes" (yea I'm not getting over that, because that's exactly how people think about this situation) who are welcome with open arms and get free housing and care. Because all war refugees are equal, but some are more equal.
But some black kids? If a couple hundred drown, that's just less problems for the western countries.
That's how it works.