Your relativism is showing again.
I don't see slavery as the sole and only reason for secession and war because of that southern nationalist sentiment, because the Middle South wouldn't have joined the rebellion just for the sake of slavery, and because political compromises had twice prevented the slavery issue from producing war.
Good, and as I said earlier, that places you several steps ahead of many of the McPherson and Jaffa types. You obviously lean to the northern side as I do to the southern, but unlike the cause reductionists who shout "slavery and nothing else" (or "tariff and nothing else"), we can at least come to some sensible ground that these attempts at reduction are foolish at best.
But there are those who aren't contented with such a view and want to go still deeper to find an underlying "strong" or "deep" explanation that will account for more.
Allow me to note there that doing so is heavily prone to fallacy as some things are simply irreducably complex - there's a certain point beyond which the war simply cannot be itemized without serving a detriment to accuracy and fact.
I don't regard McPherson's article as objectionable. He bases his conclusions on Rhodes's own findings from long ago. I tend to regard those "accidental" or adventitious" factors as more important in history that any one big cause. But McPherson certainly does make a plausible case.
I again disagree, as many of McPherson's statements in that article fly in the face of clear cases of fact. They're simply in error and inexcusable from a supposed historian of his credentials. I have detailed the errors previously for that particular article if you don't mind taking the time to find in on FR a while back. In this article for a popular audience, he's looking at the "big picture," rather than the individual and subjective factors that motivated men to fight.
The problem with his "big picture" though is it is erroniously simplistic and errs factually in several cases.
The language of the "single cause" will offend many people, but what explanation or reason or cause can you give that will explain as much as McPherson's?
Depends. If I wanted to be historically accurate, the task of a "single cause" is not possible without severe damage to factual presentation. If I were willing to take the approach McPherson does in that article and simply neglect parts of history that don't support my "single cause," I could theoretically claim that cause to be practically anything.
No. The answers people get are what they arrive at when they stop investigating. Some answers are manifestly false and others manifestly true, but history can't be reduced to provable equations. It has as much of art to it as science. I have indicated some of the reasons why one interpretation must be prefered to another, but it's more productive to regard theories more as working hypotheses than as dogmas. Some interpretations are manifestly absurd -- I'd put some of the neo-confederate interpretations in that category -- but investigation goes on and on. There's always something new to be found and historians pride themselves on coming up with interpretations that are new, original, and yet true to the facts.
You may put down Epperson, but until reputable academic historians deign to dispose of DiLorenzo's mishmash, Epperson does bring together many of DiLorenzo's dubious points. Readers are at liberty to evaluate the criticisms as they see fit, but they do indicate a sloppiness in DiLorenzo's work, which others can examine at greater length.
And understand, too, that the article by McPherson that you link to is a popularization and a simplification of his work, which is more complex and nuanced. There may be better historians out there, but DiLorenzo doesn't hit the mark. The best I can say, is that as a historian, DiLorenzo may be a passable economist.