While that's one interpretation, there's Long been conflict in the US on the rural-urban axis - see Andrew Jackson's vision versus Alexander Hamilton's vision
Race is only useful in this sort of thing as a predictor of rough economic class, and even then it's less than useful. IOW, I don't think it's specifically race.
A better resource is "American Nations: A History of the Eleven Rival Regional Cultures of North America" http://www.amazon.com/American-Nations-History-Regional-Cult...
A better analogy is the way Europeans come to America, visit New York City and L.A., and think they know everything about the nation as a whole, as if the U.S. is a homogenous culture, rather than a conglomerate of roughly 10 or 11 different cultures. The worst part is that the majority of Europeans (yep, I'm generalizing) I encounter seem to think that the massively exported American pop culture is representative of U.S. culture, when it is absolutely not. I grew up in rural Appalachia (West Virginia, western Virginia) and the culture for both business and informal activities is vastly different than that of the Deep South, West Coast, Mid Atlantic, etc.
See this book: http://www.amazon.com/American-Nations-History-Regional-Cult...
What about generalizing "western" history? There are significant trends in history like the Enlightenment, Renaissance, early Industrial Revolution, the rise of Protestant Catholics, the collection of countries who worked together in the Crusades, etc, etc that crossed regional boundaries like England, France, Sweden, German, etc but were still very much a homogeneous definable group among a wider Western population. Whose societies were very similar and evolved on a similar and distinct trajectory.
Even extending across continents from Europe into North America and South America, where simply using countries is to ignore plenty of higher-level context and wider cultural trends.
Not to mention the mixed European heritage of early North Americans, which developed an identifiable wider culture (even if much of it was built on top of slavery). Or the fact even England was largely a mix of Celtic, Scandinavian, Roman, etc which can be distinguished by going back in history but merged into one culture over time, much like America did.
I get the flaws, risks, and hostility to lumping them all into "white" though, so I'm in agreement there. All analysis requires context and race is a very poor category to work with. Even the neo-nazis and Hitler seem to struggle to define what "white" means and invent categories like Aryans, to exclude obviously white people like Slavs.
But still the human brain largely works via patterns and lumping groups into categories, whether that's socially acceptable or not. So even if it's not ethically "right" I can still see why it's such a common phenomenon, despite being a poor categorization.
We should all be using cultures rather than race, ethnic group, OR country/geographic area.
"Albion's Seed" or "American Nations" should be required reading for anyone obsessed with race to really understand the flaws of racial categorization:
It should even be in high school history education IMO.