Maybe you need to read up on the rebellion a bit more.
In other words, the plight of the slaves meant very little to BOTH sides.
Well that's not entirely true. The South wanted the slaves to remain exactly where they were and were willing to secede, and then launch a rebellion in order to maintain them in that position.
When there is a rebellion, maybe so. There was no rebellion in 1861. States don't "rebel" against themselves, and the People of the State don't "rebel" against themselves or their State when they act as a People in convention assembled.
Kings cannot "rebel" against themselves no matter what they do, by definition. Neither can a People.
Your insistence that there was a "rebellion" is a flat denial of the sovereignty of the People, and of their ownership of the United States.
You've admitted that the People are sovereign, right here on this board. It took me weeks to beat that out of you, because you don't WANT the People to be sovereign -- you want a faction to be sovereign, a cabal, a club, a sodality of Non-Sequiturs to be sovereign. But you despise the People and call them in the wrong all the time, and say that they "rebelled" -- because they are Americans, and not a bunch of weenified hand-lickers.
Which is what you want them to be. Subordinate, yielding, teachable, pliable, malleable, docile, and above all, compliant.
Lie 1: The People "rebelled".
Lie 2: "It was all about slavery."
Still lying to the newbies every chance you get, aren't you?