That's like saying the TEA party can't be about tax breaks because the vast majority of them will never personally meet (seeing The Donald on a podium in the distance or on a big screen don't count) anyone in a bracket to benefit (a $200 advance on next year's refund don't count neither) from the proposed freedoms.
It's about supporting the system, not about personal benefit. Your Solomon may well have been all about the system, the way of life, without ever actually meeting a slave owner, just as a TEA partyer might be all about "not punishing success" or "what if Joe The Plumber (OK, unlicensed Plumber's Helper) makes $250K" even though they will probably never meet anyone (damned few flesh-and-blood persons qualify) who will benefit from Republican tax "reforms".
The irony is that the war, from the Northern perspective, was explicitly NOT about ending slavery, while all from the Southern perspective, all the arguments boiled down to preserving slavery. The Southern view was all about State's Rights, but the only right they cared about was the right to own slaves. The Northern perspective was about the idea that the United States is a nation, not a collection of little nations. Neither side was really about the idea that human dignity does not derive from the ability to sunburn easily.
So yeah, the North wasn't really right, but the South was really, really wrong.
Which is not to say that Solomon was a bad guy.
I just found my dead daughter's letters to her unborn (as of 9/11/2001) child. Kid is a healthy little boy now, with a new Daddy and a new Mommy and a Grandpa Mike who misses him so much he's almost crying right now. But the letters refer to Daddy (AKA "sperm donor" AKA "rapist" AKA Adam) who went to fight Al-Qaeda in order to pay for college and make a better life for the little guy.
Adam was not a bad guy for going to war against Al-Qaeda. He was a bad guy for raping my little girl and abandoning my grandson. But he didn't go to war for Christianity or democracy or America. He went to war to pay for college.
My guess is that Solomon went to war mostly to avoid getting shot by a recruiter. Maybe he colored that with defending the rights of the States, or the Southern Way Of Life (of which slavery is an integral part even if he ain't the owner). But it was probably about not getting shot right now, and impressing the girls with a uniform, and making a few Confederate dollars, and being a patriot and a Man.