Lincoln is a Lawyer...he will bring forth facts to his disposal when he thinks the time is right. He will choose what exhibit to place into evidence at the right time. Free none, free all, or free some slaves to save the union, looks good to SOMEBODY all the time. He did the "Emancipation Proclamation" when it was politically advantageous to do so, no matter how illegal it may have been instigate. In 61 he seems to have chosen one part of the issue, when latter on he chooses another segment.
The South was preaching that Lincoln's "Black Republicans" were going to free and equalize their slaves, and this was used to cause fear and terror to many of the Southern population. The Tariff, Tax, import/export issues had been going on for years, but this newer idea of emancipation was used to drive home secession to good effect.
Lincoln speaks well of the facts of some of the issues in the statement you posted...but he always had his party to push other agenda’s forward.