Totally dodging the issue. You claimed "white supremacist" was an accurate title, cited Nazis who invaded other countries and eradicated the local culture/population/racial groups without assimilating (eerily similar to mass immigration), and then immediately moved the goalposts when it was illustrated how ignorant such a statement could be.
> who isn't American?
Is this a trick question? People who were not born in America are clearly not American, save for naturalized citizens and a handful of other caveats. If you were born in Iceland, Greenland, Finland, Sweden, Norway, Denmark (just picking some traditionally/predominantly-white countries to really drive it home) and are not the child of a diplomat or even a citizen: you are not American.
Seriously: do you believe you are Japanese? If you actually are Japanese, do you think you're Peruvian, too? Are you also a Liechtensteiner? People are citizens of specific nations, believe it or not - this is not some new, misunderstood concept.
> means other than to exclude some group
Why is it a foregone conclusion that exclusion is automatically unjust?
Are countries not permitted to exclude people? Again: this is not based on race. Does one have an automatic right to immigrate wherever they please?