That's just how silly racism is. By the same token, Americans consider all Europeans to be "just Europeans". We don't distinguish if you're from Ireland or England, Greece or Macedonia, etc.
I don’t follow the “just Europeans” consideration you’ve proposed. As an American, people will inquire and make distinctions when race/ethnicity comes up. ‘So-and-so is French’, or Italian, or Greek, etc.. Usually people also mention when their families immigrated, or that they are part x/y (Irish, part German, or something to that effect).
