I've come to the conclusion that this war, like all others was precipitated and manipulated by the ruling class.
The typical southerner outside slave strongholds didn't have a dog in the fight. The wealthy slave holders owned the southern politicians in the same way special interests own our politicians today.
The entire slave economy which benefited only a relative few monetarily was threatened and the ruling class using their politicians, press, etc. responded with the proper rhetoric to rile up the masses to fight for a "cause". That "cause" was deception to promote the preservation of a more sinister agenda. Consider Confederate money art. Money art often enshrines ideals of cherished institutions. The most near and dear institution to those who printed the money was slavery.
Golden Circle bump to your super accurate post.