There is no anti-immigrant climate here in the United States. There is an anti illegal immigrant climate - hence the need for the wall or some other means of stopping the illegal crossings of the southern border...
..I am an American right-winger
You certainly are, AmeriAnn
My experience of being a legal immigrant in the US is probably completely different from your 'American right winger' perspective.
White, English-speaking Americans tend to make unguarded remarks to me because I am also white and English-speaking, and maybe they assume I share their racism and bigotry.
America was built by slaves.
It was built by people who appropriated the land of the original inhabitants, drove them off it, and committed genocide in the process. Then there was the Mexican War, known in Mexico as the American Intervention in Mexico, that resulted in American 'territorial expansion' at the expense of Mexico - much of the south west and California changed hands, iirc. More theft...
The immigrants who streamed to America in the colonial era were not vetted, nor were any of those who arrived up to the eve of WW2 apart from a medical check. Many starving Irish were turned away, only to die in terrible conditions in Grosse Isle in Canada.
Those arriving in the US before the 1960s were mostly white though, because official policy was racist. That is , apart from Mexican and Central American agricultural labourers, who were welcome because they provided the cheap labour that made food affordable. America has always been a country where the rich exploit the poor and then run laughing all the way to the bank while telling the gullible middle classes and working class that their problems are due to 'illegal immigrants'. If you are seeing a lot of dead bodies along the roads, look to meth and the opioid epidemic for an explanation, fueled by the greed of the pharmaceutical industry and home grown criminality. If you think the flow of illegal drugs into the US causes crime problems, maybe look at US policies abroad that contributed to the breakdown of society, the impoverishment of farmers, the establishment of corrupt governments which facilitated the rise of criminal drug cartels, while the US government smiled benignly because they were right wingers too.
Asians and Africans were not welcome unless they arrived as slaves or indentured workers and there were restrictions on naturalisation until 1965. Is that what you call vetting?
Followed of course by the wholesale incarceration of Japanese American families during WW2.
What you are really saying, with your emphasis on the southern border, is that brown-skinned, Spanish-speaking immigrants are a problem. Not the white ones who arrive by plane illegally.
On this day when once again a gunman invaded a synagogue and murdered a worshiper, I think you should perhaps ask for your execrable post to be removed.