Now apply that reasoning to the 50% of the population that was enslaved !
next lie !
You cannot seriously expect anyone to apply one standard to Northern Slaves, and a different Standard to Southern slaves. The United States was a slave holding nation, both North and South. Or do you consider Delaware to be a Southern state?
Legal slavery would have continued in the Union if the Southern states had remained in it, so don't try to pretend invading the South and killing all those people had anything to do with Northerners launching a war to free slaves.
They had absolutely no intention of doing that when Lincoln started the war.