The secession was stupid, but so was the war. The South doubled down on slavery in a desperate attempt to be self sufficient — it could have pretty easily been starved out over a decade, as a trickle of runaways was turned into a flood. And we wouldn’t have had many of the darksome consequences, pardon the term.
Had Lincoln not called up 75,000 troops to invade the South, those states may not have seceded. Remember, Virginia voted not to secede on April, 4 1861 and only seceded after the call up. Lincoln wanted the war and got it.