The hero we all deserve, AH mod Gregory Zhukov (back from the dead) discussed this topic at length over in /r/badhistory.

Essentially the answer is no. The Civil War was fought over the North's perceived violations of the rights of Southerners. What right were being violated, you might ask? Well lets let the state of Mississippi and their Declaration of Session answer that:

Our position is thoroughly identified with the institution of slavery-- the greatest material interest of the world.

The language of the other states declarations very much mirror that of Mississippi. Slavery was integral to the CSA, as was stated by its Vice President Alexander Stephens:

The new constitution has put at rest, forever, all the agitating questions relating to our peculiar institution — African slavery as it exists amongst us — the proper status of the negro in our form of civilization" and further that "Our new government is founded upon exactly the opposite idea ["equality of the races"]; its foundations are laid, its cornerstone rests upon the great truth, that the negro is not equal to the white man; that slavery — subordination to the superior race — is his natural and normal condition. This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth.

Slavery was the central cause of the Civil War. It was the issue that forced the Southerners to secede, and it was the issue which put the two camps into a territorial dispute which led to the bombardment of Fort Sumter.

However, after that, slavery took a back seat for a few years. The CSA never really challenged the Northern Territories, while the North struggled to deal with the influx of liberated blacks which flocked to the Northern armies. Lincoln famously stated the deep ambiguity of his position over the issue of slavery, and in conduct he was very much interested in preserving the United States over emancipating African Americans. This was a struggle which would last until 1862, when Lincoln finally made slavery the central issue for resolving the war.

But its important to separate those two positions. The south seceded over the issue of slavery. Had they not done that, there would have been no war. That affirmative decision precipitated everything that followed. Secession was not forced on them, and they did declare independents in just protest of actual tyranny. Southern politicians and landowners used secession as a political cudgel, which they used to batter down Abolitionist politicians to force either stalemate or political victories for the South. See, in mid 19th century, slavery was deeply unpopular. More and more states were entering the Union as free states, and more and more northerners were becoming vehemently abolitionist. Had the South done nothing, the writing was only the wall: the abolitionists would eventually hold enough of a majority to destroy slavery. Southern politicians used secession to twist the arm of northern politicians, especially northern Democrats, in an effort to prevent further action against slavery, and to try and destroy the longstanding compromises which had allowed slavery to survive. With the election of a Republican president, the party of the Abolition movement, southerners became terrified (even before he took office, mind you) that Lincoln would be the one to lead the last charge against slavery. They had reached a now-or-never moment in which they felt that they either had to act, or let slavery slip away.

I think you are correct but this is indeed a fine point. Slavery was the root cause. I grew up in the 1950s in the North and while no one I knew would have supported slavery, no one I knew thought Blacks were equals. My grandmother once asked me about my first big girl job in Washington, DC in 1969. She asked "Are there any colored people who work there?" I said yes and she asked what tasks they perform and I listed the same job duties I had in my job description. She responded, "Oh, my. Isn't it amazing what they can teach those people to do." I can only imagine the ignorance that existed 100 years earlier when most people had very little actual contact with African Americans and grew up taught that every Black was like Amos and Andy in the 1950s. That said, my grandmother would have risked her life to rescue any human being from slavery.