Sometimes the first bullet that flies is not the first shot of the war. Some scholars claim that the USA committed the first act of war well before the CSA opened fire on Ft. Sumter.
Obfuscating the adversarial acts that occurred before battle is joined is a choice made by historians. I recall my history teachers teaching about the Stamp Act and the Intolerable Acts prior to Lexington and Concord, but somehow Fort Sumter started the Civil War? That situation would be a lot like petitioning for divorce, getting the house in the settlement, and coming home that night to find that your ex-spouse was still living in the garden shed.
But I think it is safe to say that there were plenty of jerkfaces on both sides of the conflict, and they got a lot of good people killed, along with the bad. I can't say for certain what would have avoided the bloodshed, if anything, because we cannot A/B test history. I believe that war then was substantially similar to war now; it is usually a handful of people who stand to benefit, maneuvering other people into a false choice between losing and losing more. By the time the actual shooting starts, the bets have already been placed, and all that remains is to wait for the dice to stop rolling.
It's nice that slavery was abolished in the whole USA in the aftermath of the war, but on the whole, the UK way of doing it was much better. If the worst aftereffect they are feeling now is some outstanding 4% consols, that's hardly worrisome at all, compared to the lingering legacies of abolition in the US.