I read about his earlier. This guy was a fool. He thought he could go to this tribe, which have lived for thousands if not tens of thousands of years as they are, and convert them over to Christianity for their own good. That has to be one of the most condescending, arrogant, causes that I have ever heard of.
I doubt he was doing it for God, or Jesus, or even for the tribe. He was doing for himself. He lusted after the fame that would come if he was successful. And he likely would have brought some disease into the village which would wipe them out. They were right to kill him on the beach and leave him there with no contact. They may be primitive, but they are not fools.
The fishermen who brought him there are being sought by police. They will be charged when they are caught. That island is strictly off-limits and everyone knows it. Now they know why.