Kinda reminds me of the myth that the south was totally invested in the Civil War to preserve slavery...so many like to pretend that three years into the war when Lincoln was having a hard time getting recruits to fight it and soldiers were trickling home, Lincoln decided he needed a grand ideological and noble cause. So he created the great Emancipation Proclamation declaring the slaves in the South free...but wait...the five slave-holding states in the North were exempted and those slaves weren’t free men...and therefore we get the myth that the Civil War was fought to free the slaves. By the way they like to forget that the great Emancipation Declaration didn’t free anybody, because the president doesn’t have the authority to make law, only legislators can do that.
The Emancipation Proclamation was more of a testament to the effectiveness of Gen. Robt. E. Lee and the Army of Northern Virginia than anything else.