The guy is an idiot. The Civil War was most certainly fought over slavery. Call it states rights if you want but it was over THAT state right, not any other.
The slaves knew it. Lincoln knew it. Anyone with an IQ over 50 knows it.
American education: 12 years of indoctrination, a lifetime of undoing the damage.
Slavery was one reason, and the reason that served to motivate many people up north.
Another big reason was economics. The South sold most of their cotton to England, and imported much British goods, which were subject to tariffs. The tariff revenue was disproportionately spent on projects up North. The federal government was willing to allow the South autonomy to practice slavery, as long as they continued to pay tariffs.