The very fact that the CSA explicitly claimed that it was fighting for the preservation of slavery is enough to make it a morally reprehensible regime, regardless of the legality of their actions.
You may be radical one way, but that doesn't make me radical the other. I am philosophically neutral. Lincoln had the right to conquer the south - the Natural Right of Politicians to Conquer - regardless of why the South seceded, or even if they didn't. And I have the right to dispute the lies he and others made up about it.
I am not proclaiming the North "racist." As a philosophical neutral, that word means less to me than probably anyone on this forum. Those facts are only relevant because any compassion demonstrated by you, Maki, has nothing to do with Lincoln or the Republicans. Politicians will use people of any color as pawns. The abolition movement, which was to some extent induced by foreigners, was no humanitarian effort. It agitated for 40 years, without lifting a finger to solve the problem. The war itself probably killed 20% or more of the slave population. That's about 1 million innocents.
The Republicans did not just say they were for keeping slavery out of the west. They were for keeping black people out of the west. It is Wilmot himself that called his Proviso, the White Man's Proviso. How can they be for freeing the slaves, while keeping them out of the very places they need to go to be free? lol
If there is a Lost Cause, it inures to the North and not the South. Everyone knows why the South fought. It is the cause of the north that is elusive. It sure was not to "preseve" anything, and nothing was preserved. If you think the cause of the north is not missing, then answer the question - why doesn't Lincoln just let the Cotton Seven go? From what strategic goal is that not the right move? And if you figure out that goal, you'll have found the lost cause.