I believe a [citation needed] is required for the claim that US immigration policy is "internationally conventional".
There is of course enormous variance in how countries handle immigration, but the ethical and conventional policy could be summarized as:
1. Border enforcement. Ie, try to prevent people from entering illegally
2. Tolerance for those who are illegally present
(2) Means that a person who emigrated illegally should be able to exist outside the shadows. That is, they should be able to get ID, work, drive, etc while their immigration case is decided, often indefinitely. As well, parents of children born-in country can apply for residence in the EU, for example.
This obviously makes an enormous amount of practical sense. All of the "problems" with illegal immigration ('job stealing', not paying taxes, etc) are exacerbated when people cannot legally work. Distinguishing between MS-13 members and hotel room cleaners is harder when the latter cannot integrate.
Lastly, there is an enormous moral cost to the "crackdown" immigration policy enacted by the US Government. Undocumented immigrants live in constant fear, poverty and exploitation. This is a real ethical and moral cost for an act which is, at the end of the day, pretty benign.
The US is a nation of laws, but the punishment (Can't complain when you're exploited! Can't sign a lease! Get deported to a country you left when you were two weeks old!) for illegal immigration is completely disproportionate to the crime.