"Whiteness" as a tacit non-ethnicity is very much an accepted understanding.
It's accepted/understood because it's an intentional outcome of an intentional policy.
There USED to be a white culture, white ethnicity, white everything. (One only needs to experience American history to understand the centuries long history of white identity in America).
But due to heritage of political white supremacy, we decided to destroy ALL white identity, ALL white culture, ALL white "ethnicity", as a "baby with the bath water" approach to ending white supremacy.
I think this is why people have this disconnect between "ethnicity" and "whiteness". In this thread.
OF COURSE there is a white ethnicity, but, we Americans destroyed white identity intentionally to destroy white supremacy.
My Cajun / German great grandparents had a lot more in common with local black families than white Germans from New York. Whiteness to them was just an artificial way to segregate people.
There have been a lot of very distinct cultures held by white people -- German, Irish, Finnish, etc -- but they were all quite different.
http://teachingamericanhistory.org/library/document/cornerst...
"Our new government is founded upon exactly the opposite idea; its foundations are laid, its corner- stone rests, upon the great truth that the negro is not equal to the white man; that slavery subordination to the superior race is his natural and normal condition. This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth."
It seems that even a century earlier than your 1950's monoculture, the white people of America were not just calling themselves white, but in fact, were creating political philosophy centered around their white identity.
Not their polish, German, Irish, Finnish identity.
Their WHITE identity.
Oh wait!
Is what it is, you clearly already have your conclusion.
P.S. northern chinese make fun of southern chinese (cantonese), does that preclude their ethnicity and culture? I fail to see how targeting Irish means anything. Chinese target their own sub-ethnicities all day long. As does every other ethnic group.
He's not saying that nobody called themselves "white" before 1950.
He's saying that the demographics of "whiteness" in the mid-1800s are different than the demographics of "whiteness" now, and so the term is arbitrary.
I'm not sure why you'd conflate the two, to be honest—understanding your race is fairly necessary to understand how you're viewed in the US, and how you might be expected to behave. Understanding your ethnicity is an entirely different thing—e.g. legally, nobody cared if a person was french, german, or english if the question was 'black or white'. But you might care.