US employers often state something like:
Our policy is to ensure equal opportunity in all aspects of employment regardless of race, color, religion, sex, national origin, ancestry, citizenship, age, marital status, disability, veteran status, sexual orientation, gender identity, or any other basis protected by law.
But in fact, employers can and do routinely discriminate on the basis of citizenship. This is because of potentially expensive and troublesome visa issues. How is that consistent with the above clause?
Restricting attention to the citizenship bit, what does the above clause actually do for anyone?
How is such discrimination different from, for example, discriminating against women because they might potentially get pregnant and take time off? Or from discriminating against Muslims because they might fast one month a year and may thus be less productive during that month?