American-Americans?

Here is a map of which counties voted more Republican this year than in 2004 (in red):











And here is a map showing the largest self-reported ancestry group of each county in the nation. Blue is German, pink is Mexican, mauve is British, purple is African...and off-white is "American." That's right, the people in the off-white regions say their ancestors came from ...America.














Now compare the two maps.

Who are these "American-Americans," and why don't they like black presidential candidates?