Ahem...
They say slavery was the reason in their own words.
So you stupidly brought up the articles of secession, which state clearly that slavery was the reason for secession, to argue that they weren't seceding over slavery, even though that's the reason they give in the articles of secession, which you brought up. UNFORCED ERROR ON YOUR PART.
And I don't know how you get to the conclusion that I think everyone who fought for slavery owned slaves. I never said that. They fought so that they could own slaves because they thought they were racially superior to black people. It's the same reason you fight for tax cuts for the rich today...because you consider yourself a temporarily embarrassed millionaire whose bathtub whiskey/incest porn business will take off any day now and make you a millionaire.
SPOILER ALERT: You won't ever be wealthy, dingleberry.