In my perfect world, there would be nothing but voluntary communities, and particular communities could be as open or closed as their members wanted. I tend to think that for utilitarian reasons within the current state-capitalist system there needs to be at least some limitation on both immigration and discrimination. I don’t know that throwing open the borders and saying, “Come one, come all” would have a happy ending, just like I don’t think anyone’s freedom is being abridged when WalMart can’t put a sign out front saying, “No Coloreds Allowed.” Virtually the entire spectrum of the ruling class and the state benefits from mass immigration, i.e. more scab labor employers, more clients for social services bureaucrats, more constituents for ethnic lobbies, more voters for political parties, more students for the education bureaucracy, new parishioners for organized religion, etc. But immigration enforcement also benefits other state/ruling class interests, i.e. the federal police state, companies that get state contracts to build walls/detention centers, the prison-industrial complex, capitalist corporations that profit from prison labor, retrograde Republican politicians using immigration as political vehicle, etc. It’s a win-win situation for the power elite, and lose-lose for everyone else.
I don’t think it’s a Left/Right issue per se. Immigrant detention centers didn’t start with Trump. They’ve been around for quite a while spanning Democratic and Republican administrations. I’d argue immigrant detention centers are part of the wider apparatus of the police state/state legal racket/prison-industrial complex. So people in immigrant detention centers are in the same boat as people in jails, prisons, places of involuntary psychiatric incarceration, juvenile detention, etc, etc,etc Traditionally, the US prison system has overlapped with the older slave system as well as things like Jim Crow. I’d argue it’s also something that transcends boundaries of race, class, gender, politics, etc even if those categories aren’t irrelevant either. But the same traditional conservative vs traditional progressive dichotomy that defines US politics today has been in place for over a century with swings back and forth in different directions.
Progressives have exercised a great deal of influence over US society since around 1900 (Teddy Roosevelt and Woodrow Wilson were Progressives, for God’s sake). Progressives have long been involved in facilitating authoritarian state policies (eugenics, racism, and drug and alcohol prohibition among them). During the course of the 20th century progressives did an about face on race, immigration, homosexuality, the “sexual revolution,” etc. But they’ve still favored authoritarian state policies in many other areas. For example, the modern “war on drugs” has been supported just as zealously by liberal politicians and civil rights leaders as conservative Republicans and the religious right, and the war on drugs is to a large degree the foundation/cornerstone of the modern American police state (though there are obviously many other contributing factors).
Most progressives are not anarchists or libertarians (left or right) and don’t claim to be. They accept the supposed legitimacy of the state, state law, state penal institutions, etc. They just don’t like it when these things are used against people they like (illegal immigrants, environmental protestors, etc) as opposed to people they don’t like (the Bundy clan, corporate executives, gun nuts, racists, etc). But given their acceptance of these things, they don’t really have a principled argument against the statist argument that says, “If you don’t want to go to jail, don’t break the law” or “The law is the law. If you don’t like the law, you can work to change it not break it” or “These people chose to break the law and choices have consequences.” Once the legitimacy of the state, state law, police, prisons, etc. is conceded, I don’t know that there is a principled counterargument that can be raised that doesn’t amount to special pleading.
Of course, my view is that anarchists and libertarians who wish to be consistent should stand in solidarity will ALL persons being held by the police state and prison-industrial complex (and, yes, that includes serial killers on death row, racist hate criminals, scumbag corporate executives, pedos, and every other kind of creep imaginable as well illegal immigrants, drug users/sellers, sex workers, “consensual criminals,” self-defenders, “survival criminals,” vagrants, etc). The struggle against the state/ruling class/power elite/globalism/imperialism/capitalism/Zionism is not a “Nice People Only” club.