But no one thought that this meant that slavery would any longer be tolerated in the territories, and Lincoln was elected precisely because the Dred Scott decision was so morally wrong. And four slave states remained in the Union.
I understand your comments and know Lincoln’s position on slavery.
As Lincoln took office, he no longer had a slave problem. The states with the highest populations of slaves had seceded. This no longer affected his Presidency, either culturally or morally. The problem was gone.
With the morality argument being moot, and what was to happen in the territories being in the hands of a unified US Congress, Lincoln had a clean slate for governance.
Secession solved the problem.