When bias is caused by observing a succession of events and actions, and causes a tentative opinion to form, it is an example of generalization, the basis of learning.
When actions and events continue without interruption to reinforce a bias, it becomes a belief.
When belief prevents consideration of new information that doesn’t fit a personal generalization, doesn’t allow the belief to be modified, that is personal prejudice.
The biases and beliefs of Donald Trump have made him what he is. Reactions to what he is, are consequences of Trump being Trump.
When reactions are shared by diverse people across the world, those reactions are reasonable by basic human standards.
By those standards, Donald Trump is a questionable human being, and the country, nearly half of whose citizens elected him as their representative executive, is nuts.