The "truth of the matter" is that the Civil War was a rebellion to preserve slavery. If you really "read up on the matter", not just read southern apologist literature, that fact will become clear. The southern core slavery states seceded when a northerner was elected on an anti-slavery platform. Lincoln was more concerned with preserving the Union than with ending slavery, but his intention was to do both, and he succeeded. The Confederate flag means "band of brothers" and "sacrifice for your homeland" to some, to others it means a repressive regime that enslaved people.
Here is a link to the Republican party platform of 1860:
http://alpha.furman.edu/~benson/docs/repplat6.htmHere is an excerpt from the platform:
8. That the normal condition of all the territory of the United States is that of freedom; That as our Republican fathers, when they had abolished Slavery in all our national territory, ordained that "no person should be deprived of life, liberty, or property, without due process of law," it becomes our duty, by legislation, whenever such legislation is necessary, to maintain this provision of the Constitution against all attempts to violate it; and we deny the authority of Congress, of a territorial legislature, or of any individuals, to give legal existence to Slavery in any Territory of the United States.
9. That we brand the recent re-opening of the African slave-trade, under the cover of our national flag, aided by perversions of judicial power, as a crime against humanity and a burning shame to our country and age; and we call upon Congress to take prompt and efficient measures for the total and final suppression of that execrable traffic.
10. That in the recent vetoes, by their Federal Governors, of the acts of the Legislatures of Kansas and Nebraska, prohibiting Slavery in those Territories, we find a practical illustration of the boasted Democratic principle of Non- Intervention and Popular Sovereignty, embodied in the Kansas-Nebraska bill, and a demonstration of the deception and fraud involved therein.
11. That Kansas should, of right, be immediately admitted as a State under the Constitution recently formed and adopted by her people, and accepted by the House of Representatives.
Here is a link to Lincoln's Cooper's Union speech:
http://showcase.netins.net/web/creative/lincoln/speeches/cooper.htmThat speech along with the Lincoln/Douglas debates, established Lincoln as an anti slavery candidate, and helped secure him as the Republican presidential nominee.