If you read the articles from the newspapers printed 150 years ago, none of them use the word emancipation. The debate at that time was over the spread of slavery into the territories, as Lincoln himself stated many times. Abolitionists condemned the U.S. Constitution because they recognized it to be an ironclad guarantee protecting the rights of slaveholders where it already existed. In 1862 when Lincoln decided on emancipation and read his proclamation to cabinent members, one member was so surprised that he asked it to be read again. He could not believe Lincoln had actually used that word.
We tend to think because things worked out a certain kind of way, it must have been the plan all along. Real life rarely runs according to anyone's plans.