Of course they are people, but I think the US government should be more concerned with protecting its own citizens (voters), not the international community. The US government has an obligation to protect its own citizens above all others.
While true, those protections at their highest disadvantage the economy as a whole. France and Spain have among the highest worker protection laws, too bad though there is barely anybody to protect in the offices of French search engine, French social network, French transportation sharing network or French backoffice software outfit - foreign entities with weaker protections gained a competitive advantage and took away everyone's lunch.
It's like protecting Exchange administrators the day after Gmail for companies was released - good idea in theory.
The best way to ensure that no immigrants take urrr jawbs is to have a shitty economy. It worked great in reducing Mexican immigration during the recent recession. Of course, it caused a lot of damage for many people in the US, too.
Perhaps the best answer for everyone is to worry about growing the pie, rather than keeping people out.
Since we are forced to live in a world divided into countries, it seems fair to view your own employment position defensively.
If I'm doing a job and I get paid X, then I get laid off, but before I can find a new job I have to train an immigrant from another country to work for 40% less, I think it's quite right to view this from an nationalist point of view.