The truth matters, and you clearly don't know what it is.
It took until 1840----only 25 years before the end of the Civil War---for the majority of Northern slaves to be freed. Pennsylvania still had slaves until 1847, Connecticut until 1848. There were still some slaves in New Hampshire and New Jersey until 1865.
Anti-black racism was rampant in the North. Blacks were attacked in the streets; they had their homes, schools, and churches burned.
So you can hop right off that moral high horse.
Everything you say is absolutely true, Lincoln was no saint, and poor Irish Union conscripts did not fight to free black people. Lincoln even let Union slave states keep their slaves for awhile which was both brilliant politically and more than a little cynical.
But in the end of the day Lincoln freed the slaves. History looks at results, not character, methods, or intentions. In the end, Lincoln freed a race of people from bondage and put an end to an unambiguously savage and evil institution. Because of this, everything he and his army did is justified.