This is an illusion. The Republicans pretended to be against slavery, but they were really against the "expansion" of slavery. They were fine with it continuing to exist in the places where it existed, they just didn't want it getting any more representation in Congress.
This massive disagreement became a national political conflict, and then a civil war.
So we have been led to believe, but the schism was more about representation in Congress than it was about actual slavery. It's been prettied up to make it look like altruism, but in reality it was all self interest.
No, your version is an illusion.
The deep state progressives have been deceiving almost everyone for the past century.
Imagine what it’s like to be in a “management” position for the progressives. There’s no way you’d allow the truth to stand. Being pro slavery doesn’t look good, especially when you lose the war you fought for it, and they figured that one out pretty fast.