According to the EEOC:
"Is the charging party a U. S. citizen? If not, (s)he is not protected by Title VII or the ADA, which exclude aliens working outside the United States"
https://www.eeoc.gov/laws/guidance/enforcement-guidance-appl...
So the lack of US citizenship specifically does play a big role here. However, I pointed out elsewhere there are in some cases other laws, especially state-specific ones, which might apply, possibly :)