No, slavery was just one of the issues that caused friction.
Funnily enough, there weren't really many other issues that caused "friction", and those that did exist tend to lead back to... you guessed it, slavery. It's really astonishing people refuse to believe how thoroughly our early political life was dominated by the question of slavery. Missouri Compromise? Slavery (I would like to see this argued). Kansas-Nebraska Act? Slavery. Dredd Scott? Slavery. Harpers Ferry and the trial of John Brown which prompted eulogies, elegies, and church bells ringing across the entire North?... Yeah. Slavery was
one of the major issues for most of the 19th century, yes, but it became THE major issue in the middle of the century. You can't really get around it.
Most southerners didn't even own slaves it was really only the plantation owners who did.
This argument is as meaningless as saying, "Most northerners weren't even freed slaves, therefore they couldn't possibly have been fighting to end slavery." Of course most southerners didn't own slaves, that was a luxury. But that doesn't mean they were fighting to defend what they regarded as the ideals of a "nation".
The thing that really set off the war was that Lincoln was elected without a single southern state voting for him.
Also an odd proposition, and more or less irrelevant. Firstly, regional divides in politics happen so often that if this was what really what set it off, we'd have a Civil War every other political cycle. On top of that, you're confusing cause and effect. It's not exactly as though they weren't voting for Lincoln because they universally disagreed with his foreign policy.
Prior to the mid-1800s, the United States was fractured along many more numerous regional lines -- the south, the northeast, the middle, and the back country. The latter three consolidated into one bloc because of the question of slavery -- there's not really another unifying factor that satisfactorily explains it. American politics fractured along northern-southern lines because of the slavery question.
And it's not like this issue was a freakish one in the 19th century. The slavery question was one of the major problems that
every nation was confronting in the 1800s.
The south felt that the north was out to remove their states rights, the particular issue the north was focusing on was slavery but the souths main concern was their rights as states in the union.
Their rights to own slaves. There weren't really any other rights that the north was trampling on. Any other issue you might point to is not satisfactory as an explanation for this particular sectional divide. Economic policies favoring industry over agriculture? Then why wasn't it the northern half of the East Coast vs. the South and the agrarian middle? What else is there to turn to? Foreign policy? Fashion industry?
Abraham Lincoln said outright that if emancipation must be sacrificed to avoid civil war then he was willing to sacrifice it.
This quote is horribly abused and always taken out of context. First off, it was a letter to a heavily Democratic newspaper editor who he was trying to get on his side; if you think he was going to express radical views here, then I'd suggest not trying for a political career. Secondly, he later went on to say that beyond his political goal of "saving the Union", he held a firm personal belief that all men, everywhere, should be free.
Many Confederate general, including Lee, and virtually the entire rank and file of the Confederate army didn't even own slaves. So if the war was all about slavery then why did the Confederates fight? The slave owners may have had cause under slavery but why did the rank and file fight so hard?
Just as irrelevant as it was at the beginning of the paragraph.
Many Confederate deserters would take care of their families and then return to their units, the north had far less determination.
And this is what in the academic field we call "false". Northern units fought just as hard as southern ones for much of the war; on every side in the battle there were heroes and cowards. Pointing out that they existed is not a particularly useful pursuit.
On the other hand, let's take a simple example. Late in the war, when Sherman marched to the sea, his army actually grew. That's right, marching through a "hostile" countryside, which we in the military field would normally associate with "attrition", he managed to actually preside over an increase in numbers -- a situation most generals would absolutely kill for. How did he manage this? Did he have borrow an Irish cauldron? No! Southerners, mostly black but actually including some whites joined the northern army.
Meanwhile, a strand of racism comes every time the southern United States dominates the political sphere. Segregation ended a hundred years after the war. The whites restricted their rights to vote, participate in the legislature, and run successful businesses.
Frankly I don't understand why any educated person would want to perpetuate the myth that the South had any nobler goal in mind than advancing their racist institution and ideals, and continuing their outmoded economic way of life which relied on coercive labor sources.