actually yes the issue of owning slaves was one of the causes
and such an emotional cause it fanned many flames
You do point out the hypocrisy of many in the North. it does and still does exist
That doesn’t change that many more in the North and in the South knew owning slaves was wrong in every way possible.
If there hadn’t been nearly 4 million slaves primarily in the south there would not have been a Civil War
The issue of slavery did not start the war. The war began on April 17, 1861 in the President’s office. Both he and the US Congress said that the war did not begin over slavery.
You forget that there were 20 times that number in the Caribbean, Central, and South America, as well as in Britain and France. No civil wars there.
Presence of slaves did not cause the war.