That's a ridiculous statement. Secession was real, unlike your pretend gods and your pretend marriages to close family members. Second, if the South simply wanted to continue slavery they could have stayed in the union, where slavery was protected.
The south could have stayed in the Union, and their domestic institutions, unjust as they were, would have been safe. But they didn’t want that. They wanted to further and extend slavery, with an intent to go to war as necessary to take Arizona Territory, and perhaps Cuba. To do that they needed Virginia, and so they started a war with the US to bring in Virginia. And only a few years after insurrection in Virginia had been put down, they flipped and claimed no federal power to put down insurrection.
Good thing they were stopped. They guessed wrong on Lincoln.