I once saw two men down the street from me-- men come from Mexico or Central America, undocumented workers, who are probably living on a pittance, and sending the rest home to family to children growing up without them. (I am not assuming too much, that is the way things are done here. The men come first, often. Immigration, sanctioned or not, works like that.)
It was summer. They were barefoot, bare chested, bare handed. Dressed just fine for a day at the beach. But not for the arc-welding which they were doing on the sidewalk.
They don't know how things are supposed to be done. Somebody said to do it, and they were afraid to say no.
The people who just got here, people with brown skin, people who learn English when they get here, are not 'taking jobs from real Americans.' They are doing the scarey, dirty, dangerous jobs that nobody else will do. They are doing them with little complaint, often with a kind smile. They are vulnerable to exploitation, they often do not know their rights, and even when they do they are afraid to complain.