Suppose your daughter is one of two finalists applying for a job. Both finalists are US citizens. You know that the other finalist is willing to work for less than your daughter. On the day of the other finalist’s interview, you decide to use force to physically prevent him from getting to the interview (maybe you hold a gun to him and/or kidnap him) in order to ensure that your daughter gets the job at a higher salary. Clearly, your use of coercion against your daughter’s competitor is not justified and is immoral.
Now, what if the other finalist was not a US citizen, but was named Juan and he was born on the other side of an imaginary border line? Does this change in nationality change the moral equation? No. Not at all. Just because someone is born in a different place than you does not mean that it’s morally permissible to initiate aggression, coercion, and violence against them if they are peaceful (self defense is a different issue). Yet, this physical coercion is exactly what many people want our US border patrol agents to do. Generally, it is immoral for me to use violence and coercion against other peaceful people just because I don’t want to compete with them in the marketplace.
I’m not saying that you have to do anything positively good for immigrants, I’m just saying you should refrain from harming them. I’m just saying that you should not actively initiate harm against them. The “taking our jobs” anti-immigration arguments violate basic moral principles. Luckily, most economics studies show that immigrants don’t actually “take” our jobs on net overall, but even if they did (which they don’t), immigration restrictions based on that would not be justified.
The above thought experiment is based on Michael Huemer’s work, as adapted by Chris Freiman and Javier Hidalgo.