Lincoln said the war WAS NOT about slavery. He said so in plain English many times. It only became about slavery when the North was running out of Irish conscripts to put between the Army of Northern Virginia and DC. The freshly “proclamated” blacks made good cannon fodder for the butcher.
The rest of your statement is so pathetically silly I don't even know where to start. Black participation in the Union army wasn't even permitted until 1863. At the end of the war it was less than 10% of the Union army and blacks were not primarily serving in combat units. The Irish constituted an even smaller percentage -- just over 7% by most estimates. The highest I've ever seen was 7.5%.
While it's incredible the history you Lost Causers are ignorant of, it's nothing compared to what you think you know that's simply wrong.
He was actually telling the truth in that instance. Lincoln and his backers didn't give two hoots about slavery. That issue was merely a wedge in their political toolbox.