The cause for war differed depending on who was fighting.
The southern fighting man was conscripted, and fought to keep faith with other men, and to avoid punishment. Lee published orders directing that those who didn’t attack with sufficient celerity be shot. That was intended to provide additional motivation. Pickett was famous for kidnapping NC men in the US Army and shooting them. Jackson was famous for shooting stragglers, but his biographers say things like “ ... a great marcher of men”.
We know the motivation of Jeff Davis and Alexander Stephens, pretended Pres and vice pres of the pretended confederacy. They began the war to protect and extend slavery. We know that because they said so. They said that they thought slavery was a good thing.
We know that Lincoln responded to the southern war to protect the US constitution which created and established a Union between the various states. Though he thought slavery was a bad thing, he had no authority to ban slavery absent the insurrection, and supported the amendment to the constitution that eventually ended slavery in the states not in insurrection.
Lee is an interesting case. Noone ever accused him of rape, torture, or kidnapping after slavery had been ended. Noone ever accused him of having people shot without legal authority after the insurrection was at an end.
He did go to court three times in an attempt to prevent or delay the freedom granted to his father in law’s slaves. He appears to have bought kidnappped people for use as slaves. He appears to have supported torture when used against slaves. He appears to have ordered shooting of soldiers who were not sufficiently forward in battle. Many of his slaves at Arlington were mostly white, and his slave ledgers, still kept secret by the family, probably reveal his practice of raping female slaves, and selling his daughters to brothels.
Lee’s experience shows why the insurrection and the slavery that he and it supported were evil. Absent those pretended legal justifications of evil, Lee was a good man.
You simply sound like an echo chamber, and you just keep repeating yourself.
Since we don't have anything like a dialogue going on, I suppose I might as well interject something completely off the wall as well.
Why did Lincoln invoke the memory of a rebellion in 1776 where a collection of States Broke away from a government with which they disagreed, in support of his contention that such should not be allowed?
If he is opposing the right to do so, he's certainly picking a weird example to make his point.