US policy has also nearly completely eliminated the distinction, by making legal immigration close to impossible and ~arresting~ kidnapping people at courthouses who are there for their immigration hearings, then shipping them off to foreign torture camps.

I don't think that is true at all. For example, it was considered a big deal when ICE was rounding up US citizens. It caused a big drop in public trust for ICE.

Nearly half of the workforce of crop farmworkers in the US is made up of "illegal" immigrants. The US food-supply relying on those people has meant that, in practice, immigration law enforcement is deliberately selective and self-serving.

So, the idea of illegal immigration as a vice worth cracking down on and punishing has not been consistently applied by the people publicly condemning it (like this current administration), meaning there is a very real sense in which the distinction between illegal and legal immigration is not real.