Answer:
Hey there!
Basically, the Dawes Act was created to force Native Americans to join mainstream American culture, and to give up their traditions and heritage. The government broke up the Native American land which they sold to Americans, forced them to move west, or join American culture. The Native Americans of course, were unhappy with this act, and believed that they should be the owners of this land as they have been here for hundreds of years already. The Native Americans were made powerless, and forced to obey the commands of the government, so it would make sense that the Native Americans weren't happy with the Dawes Act.
Let me know if this helps :)