racism is astrology, it's not based on any objective, measurable metrics and has constantly changed throughout history. people point this out by talking about anti-irish racism, because it was a real thing but farcical under the current construction of race. Eric Foner brings up interesting points for American-specific situations where people make mistakes in their narratives---but that isn't a rebuttal to the existence of anti-(people-who-were/are-considered-white-in-the-US) racism in Europe. the white/nonwhite dichotomy itself is US-ian, not the only way to construct a racialized social hierarchy