I cannot let this piece of revision go unchallenged. No, Lincoln's refusal to ACCEPT the Andersonville prisoners had nothing to do with Confederate policy on black prisoners of war. The offer was unconditional---no quid pro quo---no reciprocation. Lincoln did not want them. Their suffering was valuable to him because just as it was seen as horrible and unfortunate by Jeff Davis's administration.
Your statement that the War was started by Southerners is hardly credible, but there certainly were some hotheads that wanted it.
There is a lot of well researched history outside the public school system. You ought to visit a college library or even a public library once in awhile.