Worst ending of all time?

It would have been a decent film for me without that ending, an ending so ridiculous it's shocking and I cannot think a movie that was more ruined by its ending.

Talk about a complete stack of "deus ex machinas:" Somehow a baby throws an oar overboard and she doesn't notice. She somehow can't paddle with an oar despite growing up on an island. Somehow an enormous shark appears so close to land. Somehow she manages to hit the shark with a 1 in 1000 throw of the other oar. Somehow the shark stays around. Somehow there is a strong current that takes them away from the island at lightning speed, despite the current brining them to the island on that very same side at the start. Somehow the Uncle just happens to be cruising around looking for them 10 years after the fact. Somehow he is still right beside that island despite seeing them on the island covered in mud and disregarding the island. Somehow a toddler is capable of harvesting berries in a container (without eating any) and bringing them on the ship. Somehow they didn't notice this container for days despite being starving. Somehow the baby eats some. Somehow, despite showing a strong will to survive at any costs, the characters commit suicide, and they don't even look thirsty yet! No dried lips or sunburns or anything. And somehow the Uncle manages to reach the children perhaps minutes after they took the berries and "fell asleep" (as opposed to writhing and vomiting, what would actually happen).

Why did they ruin the film this way?