Good points. I think it would be interesting for a grad student to look at how the idea that the South was Celtic and the North was English came about. Seemed to be a late 20th Century thing rather than something that Americans North or South thought about in 1860.
You do see some Southerners describe themselves as Cavaliers as opposed to New England Roundheads. But that is a distinction between rival groups of English.
As a 7th-generation Southerner with Welsh and Irish roots (DNA confirmed), ancestors who arrived prior to the Revolution, I was researching, and read that
in the 1600-1700's the exchequer of each port city determined which country of origin to admit, through a strict though subjective vetting process, and New England historically preferred English well into the 19th Century. Also, I learned that there was
a great out-migration of Scot-Irish from the North into the Southern Wilderness, because of disparate treatment by English-born citizens in the North. I have relatives of one line, who still live in New York and who arrived on the North American Continent before the Revolution, when dumped off an English ship onto Nova Scotia, likely for their religious beliefs. Today, no doubt those of my New England relatives unwittingly claim to be blue blood British.
As for the vetting, for example, it was
not until the 1760-1770's that people from the British Isles of Scotland and Ireland, and Wales, were allowed into the Port of Charles Town, South Carolina. Before that era, they arrived in droves into the South through out-migration from the North. That leniency in South Carolina only happened when it did,
because the Exchequer was himself from Wales.
Those Welshmen arriving in Charles Town were pushed out of the city to live along the Pee Dee River among other societal misfits: the Quakers, French Huguenots, Creole, Melungeon, mixed-breed Native Americans, and free blacks. Later generations were pushed further away from the coast, by economic, political, religious, societal pressures, including torching their farms and "running them into the wilderness like dogs"... their words, not mine. Today, travel to that area in northeast South Carolina just off the Atlantic coast, and you'll find their remnants in historical museums, cemeteries, and town names.
I learned that this strict vetting of immigrants continued after the Revolution too, but not that the degree it had previously. A Civil War was coming, even a fool knew this fact, and soldiers were needed.
To understand this vetting dynamic and social conflict, go back in time to Europe. There was a great power shuffle among the classes in the melting pot of the world's immigrants because,
before arriving on our shores those same groups were looked down upon in Europe (Irish, Scots, Welsh... who during the Reformation had been forced out of England, and some dumped off ships in Canada) were demeaned here in America too, relegated to menial positions, were servants of the "blue blood" British, worked in mills, mines.
Of course, the Southern elite claimed the be blue blood British, whether true or not, and could because they did not have DNA testing. They had money which bought power, and they also relegated the poorer classes, first into the wilderness and then into mills and mines, where most never had a chance to better themselves, until their descendants did after WWII.