As usual, you take a sentence out of context and think that "is" Lincoln. Lincoln's greatness was that he had already forced the issue of emancipation by the time he uttered those words. It's almost like "plausible deniability." He knew what he had done.
"My paramount object in this struggle is to save the Union, and is not either to save or 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." August 22, 1862--A. Lincoln
I took no sentence out of context. Deny he said it? Deny he meant it?
Denial yourself?