I think most would agree that the chances of a passenger getting out alive, without any training, is virtually zero. The question is, could the pilot have helped any of them get out alive if the pilot tried.
From the link I posted above, it is obvious no one, including the pilot, had flotation vests on.
So here a a pilot, not an Olympic swimmer, maybe not even able to swim across an Olympic size pool in summer weather, barely made it out, in shock from the cold, no vest, poor swimmer (maybe).....going back in was probably beyond his physical capabilities.
His landing was under control. Up to that point, it appears that he did his part. Beyond that point it is seriously unfair to criticize or even question his actions.
Unless we know that this accident is a result of pilot error, questioning his actions is very unfair.
I forgot to add that to go back in the flopper, he probably would have lost control of the raft. You can bet he had a death grip on it and there was no way he would let it go floating down the river without him.
If you google the east river, you will find out that this time of the year it is very cold.
https://www.answers.com/Q/What_is_the_current_water_temperature_of_the_East_River_in_NYC
That would just about stop your heart.
And in other links, you will find that the current is quite strong a treacherous.
No way he would let go of that raft.