That’s a tough question. As the linked article mentions those tribes are usually aware of the existence of the outside world and that they have superior tools and technology.
A perhaps not completely crazy comparison is see that situation as similar to our situation with extraterrestrials. If we just for a second assume that there are really UFOs of extraterrestrial origin, at least some of us “know” that they exist and have superiors tools and technology. Of course, there’s no totally compelling evidence that extraterrestrials really visit us with their UFOs, but it’s a possibility. But in the case that they actually exist and observe us, do they try to follow the “prime directive” from Star Trek? And will they show themselves openly when we reach some technological or social threshold? I think the answer is probably yes – after all, that behaviour would closely mimic our current behaviour towards those “uncontacted” tribes.
Would it make sense to apply the “prime directive” to “uncontacted” tribes? Well, what chance do they have to develop an industrial civilization within the next 1000 years on their own? Virtually none! If they want to contact us, we should provide help in the most benign way possible. They already know we exist, so showing ourselves to them shouldn’t harm them too much. The greatest problem really seems to be lacking immunity to “our” diseases. That’s a tough nut to crack. Maybe we should wait until we have the medical technology to immunize the tribes against the diseases to which we already have developed some resistance or immunity. Also, our current level of wisdom is still relatively small, so any kind of contact should be done really carefully and thoughtfully.