There were several reasons why American Indians tried to stay neutral during the American Revolution. Here are two possible reasons:
American Indians had mixed feelings about both the British and the American colonists. Some tribes had been allied with the British during the French and Indian War and had good relations with them. Others had traded with the colonists and valued their economic ties. Therefore, some American Indians did not want to take sides in the conflict and risk damaging their relationships with either side.
Some American Indian tribes believed that the war was not their fight. They did not see themselves as British subjects or American colonists, but as separate nations with their own interests and sovereignty. Therefore, they preferred to stay neutral and avoid getting involved in a conflict that did not directly concern them.