A tiny minority owned slaves. The South fought the coercion and tyranny the North, and for the very dirt below their feet.
Tell me -- why didn't the northern states who also legalized slavery then also fight WITH the South if your claim is THE case?
The percentage of slave owners varied from state to state. The more northerly border states tended toward single-digit percentages. The deep south ranged from approximately 34% to 49% in Mississippi - http://www.civil-war.net/pages/1860_census.html
The South fought the coercion and tyranny the North, and for the very dirt below their feet.
There was no tyranny - except for the tyranny they perpetrated upon their own populations.
Tell me -- why didn't the northern states who also legalized slavery then also fight WITH the South if your claim is THE case?
The north went to war in response to being attacked by the confederates and with the aim to save the union. The south went to war to defend slavery and lost everything.