In fact, the incarceration of children whose parents are in violation of rules about migration is a global problem. I was recently impressed by some discussion of the growing problem in my erstwhile home, South Korea, where it is normally an untouchable subject.
You can read about it here. The below video is included on that site.
irreversible effects of immigration detention on children (full version) from APIL Korea on Vimeo.
My important point is that the recent outrage among some parts of the US population about this issue is in fact quite narrow and parochial. This is a global problem and the US is at best a minor violator. That doesn’t excuse it. Rather, I think this core problem of child punishment for parental behavior is key to understanding why migration restriction regimes are on par with chattel slavery in ethical terms.