The USA has a history of doing racism based only on skin colour. But in many other countries there have been "culture" /"ethnicity" based racism. This is what your noticing. Accent (ie. culture/ethnicity) racism.
Racial/cultural/ethnic prejudice is an attribute of human nature, not US culture, so while not singling out the USA, the USA certainly did also have discrimination not based on skin color (jews, irish and other immigrant groups, catholics, etc. have all suffered discrimination to various degrees). None as overt and officially sanctioned as the segregated South however.
I am well aware other countries have racism problems. I pointed out USA because a lot of people here are for USA, and it's a got a great example of skin colour only racism.
