To protect US citizens there are laws in place. That however can be chipped away piece by piece. If tech companies had their way that would end.
There is a real concern about the (at least perceived) decline in the US standard of living for low/middle income folks, that is not necessarily anti-immigrant. You can't deny, immigrants built the country. However, America is going to have to deal with this problem of preserving the very ability of its citizens to be upwardly mobile. I'm not sure how much of the fear is real, but its out there.
The reasons and successes of the past does not necessarily guarantee success by following the same pattern today. Saying something was good before doesn't provide a free pass from questions on the validity of repeating policies of the past.
Not that I'm stating an opinion on the matter one way or another, but I would say the question is valid and your answer comes across as dismissive.