Barriers to integration into the community
The destruction and exploitation of the environment — such as deforestation for timber and farms — puts many tribes at risk to the environment and their lives. Being in the mountains, from generation to generation, they get used to this lifestyle and environment. Even the Brazilian government and other advocacy groups must find ways to protect vulnerable tribes without interfering with them. Contact and integration with the civilization of the modern world seem to be quite difficult.
Because the adventurers came here, approaching them with an unforeseeable purpose. Not everyone with good intentions wants to learn and discover the culture, sometimes they bring danger. The knowledge of these tribes is irreplaceable and has been developed over thousands of years. Subconscious things are hard to change. Finding the roof of the problem is not all. Another matter is how the people of the other tribes understand modern life.
Humans took millions of years to evolve and rise from the life of primitive man. They need the civilized environment, collective life, and time to change and accept. The fact that these tribes are more open to the world must go hand in hand with the acceptance from the people of the civilization for the integration to be effective.