If people on the Sentinel Islands are people, really people, we would consider it a crime against humanity to let them languish imprisoned by the sea. But we don’t consider them people. Our treatment is the same we extend to apes. Mute indifference to suffering.
Leaving primitive tribes uncontacted is fundamentally contrary to human dignity and equality. Their way of life is worse. We have the ability to improve it, but choose not to, because we do not really, truly believe they are human. We treat them as animals on a game reserve.