After the Confederacy first provoked, then started, then formally declared war on the United States, then sent military aid to pro-Confederates in the Union state of Missouri, then Lincoln had no choice except to defeat the military power which clearly threatened to destroy the United States.
Freeing slaves was a tactic in that war, but it was also something that Lincoln had long considered a long-term goal.
You mean he was lying all along, sort of like that other lawyer from Illinois that was against "gay marriage"?
So does this mean the people in the South were right to not trust him? That they called him out correctly?
Yes, Lincoln started out with "If you like your slavery you can keep your slavery." And of course, just like that other Lawyer from Illinois, that simply meant until he changed his mind.