Why did the Oneida warrior believe that his brother merited death?

The Oneida warrior believed his brother merited death due to perceived betrayal or actions that threatened the tribe's values and survival. This could stem from the brother's alignment with enemies or a failure to uphold the principles of loyalty and honor essential in their culture. The warrior's conviction likely reflected a deep sense of duty to protect the tribe and its integrity, viewing such drastic measures as necessary for the greater good.