When differing civilizations encounter, what do you think happens?
The more technologically advanced exploits the situation for profit, no matter what the cost to the less advanced.
Native Americans and the Indian civilizations in Mexico come to mind as the closest.
As soon as the Brazilian tribes sit on oil or gold, they'd better watch out. Someone will want to plant a McDonalds there, and put 'em to work in the fields so as they can buy a hamburger.
That ISN'T to say there aren't enlightened folks who are altruistic, kind, decent, etc. I know a whole lot of those.
And I be heeled.
Arf