I think Southerners might disagree with that point, especially through the post-Civil War Reconstruction AKA military occupation period.
Not saying they're directly comparable, but "nothing like you've ever seen in America" significantly overstates the differences.
Militarily, while the Civil War is in some ways a prefigure of WWI, the comparison only usefully reaches so far. In particular, Civil War artillery lacked the absolute primacy achieved by later developments, permitting a much more mobile style of warfare and preventing the stasis observed on the Western Front. The Civil War's belligerents were also much more unevenly matched, making it possible for a single engagement to produce a decisive strategic outcome; no such possibility existed in WWI until much later in the war, when new technology came along to counter the primacy of artillery and break the stalemate of the trenches.
Politically speaking, too, we observe a qualitative postwar difference; harsh as the military occupation of the South was in many ways, and in spite of bastards like Butler, there existed a strong desire for conciliation and reintegration of the erstwhile secessionists, which overall found considerable success; while the cultural and economic differences underlying the war largely still exist to this day, we've just passed the sesquicentennial of Appomattox without at any point seeing a serious desire for, or risk of, a new outbreak of warfare. Versailles, by contrast, while no doubt seeming justified to its authors in the astonishingly punitive terms it imposed, produced a new and much uglier war within just a few decades.
So, no, I can't really agree with you here. It's accurate to say that the Civil War is by far the ugliest war whose effects our young nation has ever directly felt. It is not at all accurate to say that those effects are in any way comparable in severity to those of the First World War - which, indeed, was nothing like we've ever seen in America, a fact for which, should you be so inclined, I recommend you nightly thank God.
While I'll agree the desire for conciliation was much strong, on the other hand, the harshness of the occupation, the severe losses of wealth ... I too have Southern roots, my mother is Cajun, and one story in her family history is how a great-great or so grandmother kept the Damn Yankees from stealing the family horse by wrapping her arms around its neck and just not letting go. The South indeed started from a lower base, and was sufficiently knocked down that a new war was not in the cards, on the other hand, resistance to the military occupation was also harsh and didn't end until it ended.
Some don't count overall conciliation and reintegration to have been completed until 1994, when the Republican capture of the Congress included hitherto unseen gains for the party in the South.
And let me emphasize, as I noted to masklinn, I'm not focusing on the winners except as that is relevant to the losers.
Trust me, WW1 in Europe makes the American Civil War look like a nice picnic with the kids in a park.
The continental "winners" of WW1 suffered more than the losers of the civil war.
Check out https://populationpyramid.net/france/1950/ and https://populationpyramid.net/germany/1950/ there are two features you can notice on these: one is a belt at the 30~34 level which is a birth deficit from the WW1 (combined with WW2 losses), the second is that the male side has a giant bite taken out above the 45-49 line, those are the deaths from WW1, 30% of the male cohorts of fighting ages were lost in the trenches, parts of the battlefields between Belgium and France are still completely unfit for any human activity, they remain "red zones" a century later[0] with poisonous compounds (e.g. arsenic) representing double-digit amounts of soil, and even in "rehabilitated" areas of farmers keep harvesting iron[1]
[0]: http://www.nature.com/nature/journal/v538/n7624/full/nature1...
ADDED: you'll find it about as difficult to get adult or thereabouts first hand experiences from the pre-WWII German era.