That is in my opinion 90% of the entire reason that Lincoln issued the E.P. was to placate England to keep England out of the War on the southern side.
He would not have minded if England were to have entered the war on his side to aid in the blockade and intercept the commerce raiders like the CSS Alabama, now would he. THAT simple fact alone should tell historians something about the nature and the aims of the war prior to the E.P. That the war was never really fought to free the slave either before or after the E.P. like waving a red flag in front of a bull. The fact that England (an anti-slavery nation, who was the world leader in trying to stop the slave trade altogether) was even feared to be considering entering the war on the southern side should tell you what they and the ex-Lord mayor of London thought about the moralities of the northern aggression and who they held responcible. But politics are what they are.
The other 10% was to placate the Radical Abolishionist within his own political party. Lincoln was a totally political animal