Prejudice has long preceded the debate about illegal immigration in the United States, though to be fair, prejudice is very much a natural by-product of human cognitive systems.
Human beings are hardwired - so to speak - to regard those who are different from us as unfavorable, and even if we may have no explicit prejudices against a minority group or those who belong to another ethnicity, there are uncontrollable, unconscious, implicit prejudices within us toward certain races that can affect our emotions and reflexive reactions. Only when explicit prejudices are consciously verbalized or otherwise acted upon that they become the most damaging.
Immigration, for millions of people since the country was founded, has been a wholly legal process and a source of great pride to those who achieved the ability to live and work permanently in America by rightful means. Illegal immigration, meanwhile, has led to much discrimination against ethnic groups, and unfortunately, often legal immigrants within those groups also unfairly receive harsh treatment by other Americans – as some of them insist, "true Americans" – for the offenses of those who did not follow the law. Clearly, this is an ugly aspect of immigration for America.
Immigration for America also may lead to instances of discrimination with regard to the mere skin color of those who come to the United States. Lamentably, in some people's frustration over the persistence of illegal immigration in this country, they will insist on using shady practices and racial slurs against ethnic groups like Mexicans. Though this cannot be implied of all employers of illegal aliens, some may relish in the opportunity to pay their workers less based on racial prejudice and not just economics.
In addition, unlawful immigration to the United States may potentially prompt the use of negative stereotypes by employers and everyday people alike. As a result, the stereotypes attributed to all Mexicans - however unfounded - may have been shaped unfairly by adversaries of illegal Mexican immigrants, even though they have a job and are hard workers.