There's prejudices here certainly but race wouldn't really be a significant one. The child of African immigrants for example would face much less discrimination than certain inner city Dubliners or travellers. The "group norm" would be more associated with our accent, so again a second generation immigrant is seen to be more Irish/normal than an Irish American.
So no I don't think I'm racist, but more because the prejudices I grew up around didn't take that form.
There are of course people who'd be prejudiced against and insulting to Africans, but they'd generally have equal dislike of any large immigrant group such as Poles or Lithuanians. Also "Black" immigrants here are Africans of distinct backgrounds, often speaking completely different languages from opposite ends of Africa so they don't form a clear ethnic group.
So no it's not a significant divide, certainly an order of magnitude less than traveller discrimination.
The racial issue in America is very particular to its history of slavery and what followed as nwr said.
Well I would say that one shouldn't be surprised that events 150 years ago have ongoing effects. The famine happened that period of time ago and still has strong sociological effects, the Flight of the Earls was over 400 years ago and similarly shapes the country. The particular social dynamics differ in each case, but to me it's obvious that such a significant social structure would shape people's attitudes for centuries.
Well we've had massive shifts in culture and attitudes and yet Traveller prejudice is just as strong, if not stronger, as it was 150 years ago. All it requires is such shifts not affecting how people are raised to view that group. It's fairly clear to me that "White" people in America have a received way of interacting with "Black" people and that has simply being consistently maintained in the culture, with just the average expression moving away from the most egregious racism.
The only African-American I've ever worked with specifically said to me that "you guys don't really act white" and specifically mentioned how we made tactile contact with him, such as back patting, nudging during a joke etc. It seems to me there's definitely norms of interaction maintaining this stuff.