why did the Cherokees feel betrayed when the Indian removal act was passed in 1830?

Answer 1

The Cherokees had done an excellent job of adapting to and integrating with white society. Then they were uprooted and moved.

Answer 2

"It was the state of Georgia that first attempted to use law to resolve the political and economic conflict between itself and the Cherokee. It did so by passing a series of state laws directly challenging Cherokee sovereignty: extending the jurisdiction of Georgia courts over crimes by or against Georgia citizens committed in the Cherokee Nation; declaring the Cherokee as merely tenants at will on their land; making all white people living in the Cherokee Nation subject to Georgia's laws; and declaring all Cherokee laws and customs null and void as of June 1, 1830. At the same time, state officials authorized the Georgia Guard militia to conduct a campaign of violence against the Cherokee to increase pressure on them to give up their land and move west. President Andrew Jackson did not respond to Cherokee petitions for assistance from the federal government, believing that Georgia's actions were lawful and justified and that removal to the west was the best result to be hoped for (pp. 46-48, 63-86)." (http://www.h-net.org/reviews/showrev.cgi?path=1909846636459)

Have you ever heard of the Trail of Tears?
http://www.cherokeebyblood.com/trailtears.htm

Betrayed is a mild way to put it.

Cheers,