The South had cotton the North needed to make into cloth.
If sold to cotton-hungry Europe, they could get a better price; the North didn’t like that.
Slavery was wrong, but the North did to the South what King George did to the American colonies with the Navigation Acts.
Slavery was a factor, sure, but the notion is was ALL about slavery is wrong.
Why wasn’t Mexico in the cotton biz too?
between 20-25% of each years cotton crop went to the textile manufactures in the U.S. mostly in the Northern States. The balance was shipped to Europe.