Both the far right and far left throw around accusations of "ethnic cleansing." Both are ridiculous, but considering the U.S. population shifted from 85% white to 55% white in the last few decades, and even today most immigrants come from Mexico, India, China, etc., there really doesn't seem to be much evidence that we're actively trying to limit the flow of non-white people into America. Besides that, there are valid reasons why people want to limit or increase immigration that don't justify hysterical accusations of ethnic cleansing.
Ethic cleansing is something much worse when that race you are "cleansing" is already living there (Israel removing Palestinian from Gaza)
The accusations is just racism. The fact that Trump gave extra fast visas to white South Afrikaans makes you think that there were some racial reasoning there.
In the last decades the whole world is more global.