I think you have a very idealistic, but inaccurate, view of the matter. Abolitionists were a despised, very small minority, and rightly so. They were genocidal fanatics. “Union” and trumped outrage of Sumter were the themes that were used to sell Lincoln’s war. The “revisionism” in the history of the war is mainly Northern, an attempt to whitewash an unlawful war, the dictatorship of Lincoln, and Northern war crimes.
Obviously, no one wants slavery, but that was not “the cause” of the war.
And it was.
Think what you want.
And, at the time, the Confederacy did indeed want slavery, so I don’t know what you mean.
I also don’t know why you want to align your view of history with the left.
The South did in 1861. Badly enough to start a war over.