Sure, but if you go searching for alleged "real reasons" you still have to begin with those expressed by people at the time.
You can't just fantasize according to your Marxist ideology and then impose your imaginings onto historical characters.
In the examples of "Reasons for Secession" documents, they all speak mainly of slavery, though some mention other complaints too, primarily taxes.
None say anything about "Northeastern power brokers" or "money flows from Europe" or unfair laws that route trade through New York -- that's all just nonsense.
You mentioned other wars -- WWII & Iraq -- and in each case you can make a list of logical reasons, but in both the obvious reasons are the most compelling.
In WWII we were attacked at Pearl Harbor and wanted to help out our British & French allies (among others) in Europe, especially after Hitler declared war on the US.
In Iraq II there seemed to be weapons of mass destruction in the hands of a brutal dictator who appeared to threaten their use on his own people, as well as others.
Sure, today everybody mocks that, but at the time it was totally bipartisan, including a Democrat Senator from New York named Clinton.
But one thing Iraq was not was over oil or money.
So far as we know, the US spent $ trillions on Iraq and seemingly got nothing for it.
That's why today we have a president who's promised to put an end to such foolishness.