A lot of tobacco, suger cane, rice, and cotton farmers up North was there?
My great Grandfather wrote in the family bible his reasons for fighting for the South, and nowhere is slavery mentioned other than for his being against "any man owning the body of any other." Gee, sounds like a real slave owner to me, what do you think?
Your great grandfather made have had his reason for fighting, but the Southern leadership had their own reasons for starting the rebellion that sent him off to fight in the first place. And by far the single, most important reason to them was the defense of the institution of slavery.
That is akin to claiming the 2nd Marine Battalion and 101st Airborne is fighting in Iraq over oil because President Bush and VP Dick Cheney are affiliated with or involved in the oil business.
No, their reason for fighting was an attempt to thwart the formation of a centralized government which they perceived and much feared would come to resemble the monarchy from which their ancestors had previously declared their independence and protection of the liberty they fought to achieve. Swearing one's "lives and fortunes" to perpetuate that goal of freely governed states was by far more important to them than was to keep any individual or people in bonds. Slavery was an issue, but it wasn't the primary issue of contention until the North made it so and for that issue alone, many Southerners or Northerners would not have fought.
The Southerners' principle summons to service was to protect their state, which they answered - just as those of the North did. Had either been given slavery alone as the issue to fight for, there wouldn't have been any conflict or any would have been short lived, for the Northern counterparts didn't want the Negro among them and hadn't intended to battle to "free" them.
To wit: note the declining determination among the CSA to continue battling once slavery BECAME the North's central claim for its aggression against the South. Had the slaves' freedom been a paramount objective, Lincoln would have openly declared it within his Gettysburg Address, but his prime motivator was preservation of the Union. Even the Lincoln Memorial states on the right hand wall that Lincoln's objective was the preservation of the Union.
Since the latter part of 19th century, the Federal government has taught publicly educated school children "freeing the slave" as its excuse to justify centralizing its power and for expanding its control over the states and the individual. Many have accepted that excuse as legitimate, many have not, many don't care.