My first and greatest worry when missionaries try to evangelize natives is not the typical criticism of cultural genocide or destruction. As I have written before, that can be mitigated and I want it to be although the megachurch evangelicals who do missions to a place like India don’t usally try to preserve the local culture. Although, when secular people bring their consumerism and academia, they likewise make no attempt to preserve the local culture. That, however, is not the worst problem that missions have. To use the Indian example, when the British colonized India, their greatest crimes were not cultural destruction or the denial of political autonomy but the near-slave conditions they worked most of the population in. Imperialism would not have been terribly bad and the pros may have outweighed the cons if, instead of brutalizing the Indians on rice and tea plantations, the Indians had become good middle-class Victorians of the crispest English culture.
It was a case of the powerful exploiting their technology and social organization to subjigate the powerless. Similiarly, when Westerners go to a place like the deep Amazon or New Guinea, they are not just Westernizing them. That would not be wrong, per se, and it could be more easily limited. What would happen, almost invariably, and what does happen, is the tribespeople go from being big fish in small ponds to being minos in an ocean. The individuals go from being important members of their world to being insignificant peons in a globalized nebula. Which is why I, for the most part, am against evangelizing the least contacted and uncontacted tribes. If these missions were old fashioned missions of Jesuits and Dominicans running outposts of less than a hundred people deep in the jungle, it affords the natives more dignity. Which is especially important given how little power they would have left to the streets of Jakarta and Sao Palo.
As far as native groups who are somewhat integrated and whose members claim double-digit sophisticated literacy and secondary education rates, it is best to fully integrate them. For a number of reasons but, foremost, that not doing so would deny them power in a society they are so dependent on they cannot escape. In the end, it is best that they be given a full Western education and somewhat Western upbrining because otherwise they will be relegated to the lowliest positions of society and will be the subject of extremely unfair power dynamics. This is not just on an “tribal” level but on a local population by local population level. If missions do occur to in the deep wilderness, they should be done by small groups, trained in anthropology, who do as little change as possible and make the conversion and integration into global society gradual. That way to retain their relative power and by the time they are fully capable of integration that they will be prepared and less prone to exploitation by malicious actors.
Ultimately, the most important factor in this is the relative power and immunity to exploitation of a people. Opening a portal from the big world and into their small world will open them up to the power of systems far more powerful than they understand which is a recipe for the worst types of oppression. An un or semi contacted tribe is a fertile ground for sociopaths to vitctimize people. For the most part, I don’t believe my religion should attempt it, right now, until and if there is a better protocol.