Christian missionary decides to break the law to spread the faith to a group of aboriginals who are fiercely independent and isolated. Gets killed. Law says that the aboriginals cannot be prosecuted.

What a change from previous centuries where that would be cause to send in military and take over the land.

I suspect some will praise him as a martyr who died for his faith.

He certainly is a martyr, whether that is praiseworthy or not.

The Indian island is inhabited by sentinelese tribe whose number is estimated to be below 50.

Under Indian law, no outside person is allowed to land on their island and if they kill somebody, they can not be prosecuted.