A well written piece that brings up some key points, especially regarding the Emancipation Proclamation. But I think there are also some points missed. E.g. Lincoln's proclamation left out the border states because keeping on the Union side was essential to winning the war. Imagine an ultimate Union victory without Maryland, West Virginia, Kentucky, Missouri & Delaware. It's beyond unlikely.
And without a Union victory there is no possibility of freedom for slaves.
There were also regions in the south under Union control at the time of Proclamation, so it did free some slaves. More importantly it made possible the formation of negro military units.
Lincoln also played a key role in passage of the 13th amendment. Although it wasn't ratified until after his death, he died knowing its ratification was a sure thing, having passed both houses of Congress.
It's true he believed that colonization or return to Africa was the best long-term goal for freed slaves. That was a mistake. Clearly. But I would speculate that he had no model for a people, ethnically distinct, being freed from long-term bondage, then successfully integrated into society. I also speculate that he might have used the book of Exodus as a model. Freedom from slavery did the Israelites little good without a land of their own. Just as he was aware that Jewish people in the diaspora still suffered systemic anti-semitism.
Finally, his comments regarding equality of negroes were made in a debate with Stephen Douglas for the Illinois senatorial race in 1858. They're often cited by Lost Cause devotees as evidence the war had nothing to do with slavery. I admit, I'm honestly trouble to see anti-racist authors using that source to tarnish Lincoln's legacy. It implies he was unable or unwilling to change his views in light of experience. I've written at greater length about this elsewhere.