[fapjacks]

Actually, this is not true. It's a well-known problem that "uncontacted tribes" actually suffer from continual outside influence, with people living near them actively trying to "civilize" them, or people with zero consideration for the law committing crimes on or near the lands occupied by the tribes, in some cases attacking and killing the tribespeople to accomplish their goals. For example "uncontacted" tribes in the Amazon have actually recently initiated contact with local government officials to ask for help with cartel enforcers that killed members of their tribes to make room for their grow / transport operations. And in another example, the "uncontacted" Sentinelese tribe in the North Sentinel Islands has actually been trading with local fishermen for years, but it was not widely known because contacting the tribe is against the law. It was only recently revealed to be the case after that stupid American missionary went on his quest to "teach the tribe about Jesus" ("civilize them") and was killed on the beach, and the police were investigating ways to retrieve his corpse.

We absolutely do not "leave them alone". Or at least -- in the grandest tradition of human hypocrisy -- we just all agree to say we leave them alone if anyone asks, and just sort of pretend like our laws are foolproof solutions to things like preventing interference with "uncontacted" tribes, or stopping drug addiction, or preventing gun violence, or what have you.