Why were tribal leaders in eastern Washington unhappy with the initial treaty requirements

Regarding the Walla Walla Treaty negotiations, many indian tribes were not fond of the idea of sharing the lands they fish, hunt, gather, and raise cattle in with their white counterparts. Moreover, it was speculated that Isaac Ingalls Stevens, the man in charge of the negotiations with the Indians, use threats to persuade the willing tribe chieftains to sign the treaty, creating controversy.