What befalls a nation, people or citizenry knowing very little about the details of its history? Aside from repeating ignorant epitaphs (slurs) taught to the next generation, is the outcome of blindly attacking people who look different from you or don't share a similar recent heritage. For the believer, we are all descendants of Noah, his wife and their three sons and wives. What is more, the science behind phylogeny speaks to a common maternal ancestor.
The people previously occupying the land mass known today as “the United States of America” initially traveled, according to archaeology, from eastern Asia. Some archaeologists say early travelers may have arrived via boat. Regardless how people arrived, travel and migration has been a human constant for various reasons. For my recent heritage, it was a political reason (1960's Cuba). For myself and my wife, it will be a spiritual reason.
People are easily divided, polarized and suspicious of others because of what the admired say on television. Blaming immigrants seeking a better life (economic reason) when the highest government authority (federal) allows for the influx of immigration to feed the demand for cheap labor is blaming the wrong group of people. But since the populace knows little of economics and political propaganda, blaming an entire ethnic group is a stronger tool than blaming obscure laws, career politicians and the reality of how the business machine is fed. See: weak teleology.
In the ancient days of empires past (or so popularly believed), slavery fed the need for cheap labor. Today, it is a political guise which justifies feeding the buying and selling mechanism; what brings meaning and purpose to many. Politics, after all, is the management of people and resources. Some of our cousins obliviously support the very people who work against their best interests.