Hartley (1946) demonstrated that there can be a generalized tendency to reject minority groups of all sorts and stereotypes can exist apart from any need to rationalize or justify dominant-group advantages when he found that:

He found that some people will express prejudice against people who do not exist
One of the most efficient methods for a dominant group to maintain superiority and justification of their status is to ensure that majority perception against a minority group is always negative. This would lead to the creation of negative prejudice toward the minorities, regardless of the truth.

They wanted to make slaves out of them.they wanted force them to move off their landthey wanted to make them grow crops for very little pay.they refused to speak native american languages