I think what parent is referring to is the simple fact that the management making the decisions to hire illegal immigrants are rarely ( as in effectively never ) brought on any kind of charges despite it being ostensibly against the law. What we end up with a system, where companies get highly malleable ( and replaceable ) workforce afraid to raise a complaint and zero consequences for people making the actual decisions.
edit: A cynic would argue that the system is in place is working exactly as designed.
What specific action did the US government take against Hyundai here?
Or did they just gut their workforce and claim that was "enough of a penalty".
Historically the US has implicitly condoned these illegal actions by employers by refusing to ever take action against them.
There has only ever been action taken against employees, who sometimes aren't even meaningfully informed that they are breaking the law. (Certainly they often know but the employer always knows)
> What specific action did the US government take against Hyundai here?
There are levels of plausible deniability that need to be pierced for actions to stand up in a court of law. Hyundai has already claimed these workers were not employees and were subcontractors or sub-subcontractors. Just the negative press and pressure from the SK govt may do a lot in the future for Korean carmakers to try and do better checking on workers working in their factories.
The previous situation being that such raids didn't happen, at least not on this scale. So Hyundai had zero pressure to change anything, not even bad publicity or interruption to car production via 400 workers being detained.
edit: A cynic would argue that the system is in place is working exactly as designed.