It only fosters irrational hate and causes unnecessary violence.
It's not like those immigrants are occupying good paying low skill jobs that could otherwise be done by Americans. They do fruit picking in California for below minimum wage.
Immigration is used as a scapegoat.
Look at Germany. They have the same policies. They have immigration. They have open borders and they have free trade policies and they fully embrace globalism.
Yet Germany retained its high paying relatively low skill jobs and the US didn't. The reason is simply that the various CEOs in the respective countries decided on different business strategies. In the US it seems they decided to go with low cost manufacturing in China/Mexico.
Finally, people are naturally tribalistic - you can blame evolution for that one. Until we fix that, immigration will increase ethnic tensions, which serve as a distraction for corporations to use while they rob you.
But I guess I'm just being irrational..
Also, saying that people are naturally tribalistic, because of evolution, fails to take into account that we're not slaves to our impulses, and that evolution blatantly favours cooperation over competition.