I disagree.
The Emancipation Proclamation was a political act.
It is quite clear that President Lincoln disliked slavery, there is no question about that, but he freed the slaves to hurt the Confederate forces arrayed against the Federal government. He would not have and could not have simply attempted such a thing on his own if the war had not started. He would have let it be.
If the Confederacy had sued for peace early on the condition the ‘peculiar institution’ would be preserved and guaranteed, I believe President Lincoln would have agreed to it.
"… My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union; and what I forbear, I forbear because I do not believe it would help to save the Union. I shall do less whenever I shall believe what I am doing hurts the cause, and I shall do more whenever I shall believe doing more will help the cause. I shall try to correct errors when shown to be errors; and I shall adopt new views so fast as they shall appear to be true views.
I have here stated my purpose according to my view of official duty; and I intend no modification of my oft-expressed personal wish that all men everywhere could be free"
Abraham Lincoln - Letter to Horace Greeley August 22, 1862