Obviously they did not have that right, and yes, Lincoln was a dictator, and we should be grateful that he was- otherwise the union would not have held together.
I guess what I am getting at about the comments re: the confederacy is that they are anachronistic; they assume that northern soldiers were solid abolitionists and anti-racists, that northern politicians and generals uniformly viewed the southern politicians and generals as traitors; they assume that the north even wanted to rule the south like a foreign occupier for "racial justice". None of these things are true, and they deeply misunderstand the climate that led to the Civil War in the first place.
I'll never forget reading Oliver Wendell Holmes Jr.'s biography, and how he and his men by 1863 blamed abolitionists for the war, and hated and cursed them regularly. Northern soldiers ran the gamut from extreme racists (think the Wilmot Proviso- free soil types) to racial egalitarians, and everything in between. There was no consensus of what to do, except free the slaves so this wouldn't happen again.