Prejudice is a "preconceived opinion that is not based on reason or actual experience" and thus is the wrong word to have been used here to describe Trump, his message, or his supporters.
The economic destruction, property devaluing, educational decline, drugs, disease, rape, child molesting, and death that illegal invaders bring to America is a well documented fact with decades of evidence.
The leftist notion that all illegals are here to work for a better life and are good people is "preconceived opinion that is not based on reason or actual experience" and thus it is the left that has the prejudice.