Your point about possible alien intelligences is an excellent one. How would we want to be treated if the shoe were on the other foot? I don't know my answer -- I suspect I would be all for change even if it were uncomfortable. But I absolutely know that I would be the one to make my personal decision about the matter. That's not for others to decide for me.
We have a word for a situation where beings are allowed to live in fake isolation, while we secretly observe them and feel great about ourselves for letting them live as close to their natural state as we can allow. It's called a "zoo"
That's a way forward that is neither dragging them into the 21st century nor running a zoo. I'm not advocating for that, of course, just pointing out that contact/isolation is a false dichotomy.
Science fiction is great. It lets us look at some of these issues without (perhaps) so much emotional heat.
So let's assume that in the 1950s, aliens contacted the president of the United States -- a theme which recurs over and over again in sci-fi. The president decided that we were too primitive and paranoid to handle contact with a galactic civilization, so he told them to leave us alone.
What I'm saying is that whatever the nature of the leader, whether they are the president, or prime minister, or head of NATO, or head of the UN, or whoever else, it doesn't matter. They don't have the moral authority to be making decisions like that for me. No part of the social contract allows leaders to make decisions of such huge import and keep them secret.
So while I support any individual's right to be left alone and live however they like, I do not support people who are presumed leaders keeping information of that magnitude from others.
Just to speculate a bit, if you're the chief of a tribe, or part of the power structure, it probably sounds pretty good to be left alone. After all, who wants change? However if you're a mother who just watched her 5-year-old kid die from something that was easily prevented? You might have different ideas. Keeping the mother uniformed so that you can continue exercising your power over her is immoral and I do not support it.
As you point out, in the real world, these kinds of things are murky at best, with lots of little conditions and details you want to consider. All I'm saying is that it's not acceptable to simply throw your hands up and give up. From what little I know, I think the idea of repeated gentle contact -- as much as it can be done without annoying them too much -- is probably the wisest course of action. This would allow us to be sure we have made a reasonable and polite effort to inform them of the outside world, as well as trying to catch the newer members of the tribe as they are born and grow up. After all, even if you're left alone, it is reasonable to expect that you still have some kind of relationship to your neighbors.
Others are children who do not get to make a choice until AFTER they have been indoctrinated with the tribe's values.
We see the same problem in the Muslim world. In some countries, Muslim women are treated as property and not allowed outside without a chaperone. How can they make a free choice to join the West when their male guardians say "no" for them?
We're all brought up in societies which indoctrinate. We're all introduced to ideas at an early age, which we grow attached to. It's unavoidable.
India is now an "important" country. Burgeoning technologically and culturally, what it received from Britain was access to the intellectual firestorm of the Enlightenment. Hindu thinkers were involved in the formation of Universalism, the idea that all religions were different aspects of the same thing and could be united.
Of course, it cost them the pain of the Pakistan-India divide, the struggle of Gandhi, and a confusing cultural identity among a people that didn't necessarily have a singular cultural identity in the first place. But what price is too much?
South Africa paid the price, and is now among the most advanced of African nations.
Of course, most indigenous peoples just got royally fucked. Aboriginal Australians and the Maori. So I suppose your point in general holds.
Disclaimer: I am an Indian.
I am saying that the effects of colonial rule are so unstable and so varied that it can be difficult to the point of meaninglessness to say a country would be "better" or "worse" without it.
The Bengal Renaissance is a documented movement, founded and driven by people exposed to Western thought. That doesn't mean the movement wasn't theirs, that they weren't the ones producing "intellectual" information. But they were in a different place because of colonialism than they would have been without, one where Indians went to school in Britain and where people were writing letters to each other across the ocean.
Besides, my point was never that India didn't suffer; my point was to illustrate some of the advantages of colonial rule and demonstrate _just how muddy_ the interference of a technologically superior culture can become.
It's like time travel - you can't go back because you don't know what kind of effects you'll have on the future. In this case you don't know what kind of effects contact will have on their (the tribe's) future.
I wish I had 100 upmods to give. This is exactly what I was saying elsewhere, we should think about how we would want to be treated. Would we want medicine and education offered to us? Would we want the option for some of our elders to live out the rest of their lives in a traditional manner? Would we want bulldozers knocking down our trees? Would we want jobs driving bulldozers?
I don't know the answer, I just know that I'd want to ponder that for a good long while if I had to make a call.