This is an interesting question because the Church as we know it came into existence throughout Europe and the rest of the world by… well…. doing a lot of walking into places where we weren’t necessarily invited or wanted. None of us would be having this conversation because we’d either be pagan, atheist, or dead.
But since we now know better than we ever have before, we have a responsibility to be a lot more careful. That man was brave (braver than over 99% of people) and well-intentioned but could easily have been carrying something that had the potential to exterminate the entire island.
Beyond that, first contact with Neolithic cultures is difficult. It’s so often the case that they are introduced to a new and exciting culture only to find themselves exploited and exposed to the many addictive aspects of society, such as cigarettes, alcohol, and these days, smart devices.
But ultimately, I don’t think keeping them isolated indefinitely is the right thing to do either. The reason this tribe is so hostile to outsiders is because they’ve had reoccurring bad encounters going back to at least the 19th century with a British captain who kidnapped several of the island’s children. It’s a delicate situation, which is why the Indian government has put a restriction on the island.
If we truly believe that the Church is real and legitimate, then we must believe that its message and teachings bring joy to those who hear it and follow it, and joy to the fullest. To say that Neolithic cultures are free and in a state of paradise is very much false. I’ve seen a lot of comments online from people that seem to think this way, and it is naïve. That island without question has problems such as an extremely high child and mother mortality rate, sparse resources, low life expectancy, etc., as well as their own daily domestic problems. Technology, art, medicine, education, and other arts & fields are also all inherently good, but they are dangerous if not introduced carefully.