“Almost sounds a little Marxist/Socialist doesn’t it.”
No, it doesn’t. Marxists are ideologues. Lincoln was operating acording to practical considerations. I get sick of the idolatry, but there were real problems involved.
For one, he had no authority to free slaves within the Union, per Dred Scott.
Second, one wouldn’t want to risk alienating the border states in the middle of a war that’s not going all that well to begin with.
Third, even if it wasn’t like a thunderbolt from God that broke the chains, at least it finally made the war about slavery (to some degree), which was better than the previous cause. “Union!” Pretty empty-sounding after all these years, right? Maybe that’s why people barely talk about it anymore.