I think it's because when we invent television we don't lose anything. Once we show these people the modern world, there is no going back. It makes it a difficult moral dilema.
Cars viciously destroyed the role horses play in our society, that part of our culture is forever lost.
(I’m not sad.)
They know all about technology, they just make certain choices about it and we have found a way to get along with them making those choices.
The whole question of whether we should in principle allow access seems easy to me but I also think that many massively underestimate the enormity of that task. I fit the culture I’m living in because my parents invested massive amounts of energy, time and money over two decades to make me part of that culture. I would guess that a similar effort would be required for the individuals in that tribe and they have no parents to help them along.
Much can go wrong. Individuals of the tribe might end up much more miserable or, indeed, dead. This is one of those problems that seems to me to be in principle easy but in practice extremely hard to actually solve.