They ought to be dragged off their island to face justice for murdering people. Justice is a universal human concept.
Yeah, that’s gonna work. Again, no language in common; no experience with (or consent to) outside legal systems. I understand the principle you’re trying to defend, but some things just aren’t workable.
Further, while “don’t murder” is likely a universal precept, it takes a lot of experience and thinking for a culture to expand the idea of murder from “don’t kill other innocent members of our group” to “don’t kill any innocent person.” Even we, allegedly advanced and sophisticated and with the advantage of knowing God’s Word, don’t always manage it.
And, of course, even if the people in question do have universal concepts of humanity and the wrongness of murder, cultures differ in what they consider an innocent person. “Trespassers will be shot; survivors will be shot again” is a half-joking sign you can find in rural areas of the United States. If these people consider their island to be theirs, and off-limits to outsiders, then killing an interloper (especially a multiple offender like Chau) is no more murder than a homeowner killing an intruder. An American can hardly call other people savages for having an equivalent of the castle doctrine.
Further, they are a sovereign state. Literally, they are defined as such in Indian law — and surely, even if they weren’t, the very universal principles of justice you cite would require treating them as such. You don’t go snatching the citizens of a sovereign state to try them under foreign laws.
It’s ridiculous to force these people to live in these uncivilised conditions through forced isolation by the authorities. There’s always a way to open communication with a culture. We should try and do that and actually communicate with these people. It’s only then we’d truly know what they want. You can’t assume people wouldn’t want to join the rest of society if they don’t even have a chance.
They know about us. They like some of our goods. They don’t let people visit for more than a very limited time, and not always even that. Sure, they don’t know the full extent of what the rest of the world has achieved in terms of medicine and other technologies, but there are limits to how many people we are willing to assault or have assaulted in order to explain that.
In case you missed it before, the Sentinelese have no immunity to foreign diseases. Europeans killed 90% of the population of North America just by bringing germs here, before they even started killing people on purpose. If you value these people’s health, we shouldn’t go near them.
However good our intentions, you can’t just integrate Stone Age people into the modern world by fiat. Even if they were more amenable to discussion, they have no context for understanding the outside world. I don’t think they’re intellectually incapable or anything, but at least at first it would be like aliens abducting them or sticking them with needles or whatever. I understand that you’re okay with forcing ourselves on them, but I am not, and neither is the government of India.