What is so bad is you making the decision for them -- one way or the other. It's that kind of pompous paternalistic attitude that caused all kinds of pain and misery.
If they are happy with a life expectancy of 30, of having mothers die in childbirth commonly, of dying of things like scratches and measles -- if they want that life, let them have it. But show and tell them what they are missing and let them decide. Don't arrogantly assume that there's something romantic about living like a caveman. It's just as whacked as automatically assuming they would want all of the modernity we enjoy.
What we've found, over and over again, is that contact with primitive cultures destroys the cultures. That's because you'd have to be a flaming idiot to want to live like that (I find the greatest supporters of "leave them alone" are armchair philosophers living all nice and comfy in the west) We can't help that, but it's no excuse to let people suffer when we can help them stop if (If they so desire) There is nothing noble in inaction.
Treat people as you would like to be treated if you were them. It's really very simple. If you'd like to rant and rave about how much modern life sucks, fine. But don't use these guys as props to do so. They deserve better than that.
By the way, this is also a pet peeve of mine, and I come at this from exactly the opposite pov. Sometimes I think "Star Trek" has done more to muddy up an entire generation of thinkers than a hundred piss-poor colleges could have ever hoped to accomplish.