Yes, it is a fools errant to challenge truth with falsehood.I think that responding to you is becoming a fools errand SNIP
Given the cost in both finances and human suffering resulting from the American Civil War it is really almost idiotic to think that all that capital was exhausted because the common man on either side of the Potomac wanted to end the institution of slavery of which many in the north had no first hand experience with, most in the south were not directly involved with and was in the process of self extinguishment anyway. It may make some feel good to think that lofty goal was the reason but it's wasn't. Slavery exists today in some places in the world and we do not see young men willing to offer up their lives to bring it to an end, now do we?
Did "common man" vote to go to war? Nope. So who said the war was caused by the view of "common man?" No one.
Did anyone say most northerners had first hand experience? Nope
Was slavery "in the process of self extinguishment?" If true then slavery was not the cause of the war. But the claim is a convenient fiction.
Sustaining slavery is not a lofty goal, but that is the cause of the war.
And finally you did hit on one truth, the common people of the north were largely not willing to die to bring an end to slavery, but were willing to preserve the Union. Thus Lincoln talked a lot about the Union, and the evil disunionists.