That’s one of the grosser distortions of the truth that I’ve seen on the WBTS threads.
First of all slavery had been eliminated in almost every northern state, and the states that still had allowed it had paths to its elimination. It really was largely symbolic though since the slave population in the north was but a tiny fraction of the slave population in the south.
By contrast the southern states not only embraced slavery, they doubled-down on their exploitation of other human beings. They had no intention of ever letting go of their human chattel and would destroy anyone or anything that stood in their way.
The true tyrants were the southron slavers.
Well the qualifier “almost every northern state” was of little consolation if you were working on a plantation. The plain truth is the union states that preserved slavery did so longer than their southern brethren. The emancipation proclamation ended slavery in the states that seceded once those states were defeated. The 13th amendment ended it in the rest, although I would argue as did several other abolitionists at the time that it was already unconstitutional under the original bill of rights particularly with regard to pernicious legislation such as the federal fugitive slave act.
That the slavers were scum is to me a given. I simply disagree that the reasons for the invasion of the south were primarily due to some noble desire to emancipate the slaves. There was already a model for peaceably eliminating slavery that was successfully implemented by Britain. Namely paying for the slaves that were freed. That such a model was not seriously pursued prior to the invasion of the south strongly suggests that the motivation for said invasion was less noble than the historical revisionists would like to acknowledge.