On the punishment for murder end of things, they neither know or accept Indian sovereignty, so applying Indian law on them doesn't make sense. As far as the Sentinelese are concerned they're being invaded. This is more similar to a case where a soldier that doesn't know the war is over kills someone. It doesn't make sense and isn't fair to prosecute them because they're working on old information that would make the murder they committed okay legally.

I completely disagree that it's wrong to not introduce them to modern technology. To do that it would require one of us to go visit them which would probably kill them because of our diseases. I would argue it's more wrong to kill them than to not give them access to modern technology.