Earlier quoted context omitted.
Are you seriously asking why it's ethical to encourage American companies to hire Americans?
Yes. And I am looking for an answer that couldn't then be used to argue that it's also ethical to encourage White companies to hire Whites. And I'm not even asking that you don't "encourage" American companies to hire Americans. I'm simply asking that you don't ban (or make it extremely difficult) American companies who do want to hire non-Americans from doing so.
If businesses were free to reap America's rewards without contributing to America's "costs", then America's economy would (continue to) crumble as businesses (continue to) exploit that loophole.
Think of it as a "If you want to use America's resources to thrive, then you should contribute to America's economy" tax.
God is watching--do you honestly see why that policy exists? Or can you still not fathom why the policy is a good idea? Your "white" counterexample is non-nonsensical, primarily because of the Equal Protection clause of the constitution--it has always been illegal/unethical to make a racial distinction...surely this is something you've known since high school gov.