Fire Memes for Traitor Haters

Essentially. Lincoln was elected as an anti-slavery candidate, but the position of the Republican Party (THE anti-slavery party of the period) was that slavery was to be isolated and let to die out on its own, as industrial and rationalized production had begun to undermine the profitability of slavery. In theory.

Whether that would have worked or not, it was an opinion that many of the Southern slaver aristocracy agreed with - they believed slavery needed to expand, or it would die. Rather than stop for a moment and consider the wisdom of an economic system that, by their own estimates, was not sustainable, they decided that the North stopping them from expanding slavery was, itself, a form of the worst oppression imaginable (obviously, MUCH worse than literal fucking chattel slavery).

So they seceded. And in doing so, they erased all incentive for Northern abolitionists to stick to the "Let it die out quietly and slowly, or we might have a very bloody war on our hands" line, and radicalized much of the north into advocacy for the total and immediate abolition of slavery.