I didn't "purport" any such thing, one way or the other. It may be an interesting question -- but I'll leave it to you to channel their spirits for their answer.
Yet you state, with confidence, the 'Civil War' was about slavery. Be bold, be brave. Confidence should not ebb & flow out of convenience.
Why did the North introduce slavery to the South?
Why did the North maintain their slaves after those in the South were free?
Asserting the war was about slavery also asserts that a slaveless South would have been allowed to seceed. An absurd assertion. The North would not, and did not allow secession; as the conflict had little to do with slavery.
This "slavery" component is a re-write of history, as is calling it the "Civil War", and these states "United". A re-write intended to salve the guilt of persecuting a war of tyranny.
So many deceptions.
To this day(as back then), most up north readily turn over their lives, and mine, to the whim of the federal government.
Socialists rarely identify themselves as such. Deception is frequently employed to hide their true face. Born to be slaves, many are ashamed to be recognized as such.
Why on earth would anyone accept your dictates as to what their heritage is & means? Put down that burden. Release the guilt. Stop calling my honor disgusting, and accept forgiveness.