Why do most people have a problems with immigrants?

Why do people have such an issue with immigrants if technically we were all immigrants. This land belonged to the indians that we segregated to reservations camps. Now most of us have the to act offended because they are crossing borders just like our ancestor did back in the day. They do the work that most of us are too proud to do for way less than they will pay us. How is this wrong when the government does this too and outsources many of our jobs overseas. Its BS to me. Put yourself in their shoes. There is no fairness in this system as a whole anyway so why target a group just because its not your group. The greed in this country is unbelieveable. Money is spent fighting senseless wars trying to bring equality when in the end it's only going to create more division.