After reading about these troubles in the Amazon, I remembered reading some time ago a back-and-forth on whether uncontacted tribes should remain so and why it is good that they exist.
My take is that, in general, tribes/groups that are uncontacted are worse off than those that are not. No medicine, no refrigeration, no distribution network and, despite some people's bizarre notions to the contrary, not really any less violence.
But we seem to have a romantic attachment to isolated, primitive tribes. Part of it is a desire for simplicity that ignores the difficulties of their lives compared to ours. I also think that part of it is the wonder and mystery that it provides us. We know a lot about the world around us. We have mapped the surface of Mars, and yet, there are tribes of people that still exist on this planet that we don't know about. People who have never seen a car or a television still exist. That there are still people on this planet that we don't know about, who don't know about us, gives us a bit of pause to think about how much we don't know.
Scientists in particular but I think all people have a fascination with discovery. Finding something new, seeing it for the first time, being the first to understand how it works are exciting things. When we "discover" a new tribe of people we get a bit of that, but we also get to wonder a bit about what it would be like for them. Their "discovery" of our modern society would be much like our finding or being found by an advanced alien race.
So I like that there are uncontacted/unknown peoples in the world. I just don't think they are living lives that are as good as mine by a long shot.