The correct answer to this open question is the following.
Chief Seattle considered strange that the American government would want to buy the land on which the tribe is living because he questioned the President of the United States how he wanted to put a price on elements that had no material or monetary value such as the freshness of the air, or the beauty of the sky. How he questioned US President Franklin Pierce, there was a price for the sparkle of the water.
Chief Seattle's view of this land was that mother Earth was something sacred for the Native American Indians. Nature was holy for his tribe. All the elements of nature were sacred and celebrated by the Native Indians. That is why they performed dances to the elements and chants, to thank mother nature for everything it provided.
Human sacrifice and expansion was the answer because the Aztecs were a feared tribe and conquered many people. They had always practiced human sacrifice and that was one of the reasons that Hernan Cortes had been horrified about. It couldn't have been anything about conquering Mayans because their civilization had died out for some strange reason.
