By the time of the Civil War, 75% of the Federal budget was derived from tariffs on exports (tobacco and cotton) from southern ports.
I DID NOT STATE THAT CORRECTLY>
By the time of the Civil War, 75% of the Federal budget was derived from tariffs on IMPORTS on goods from Europeans whose shippers were then BUYERS of (tobacco and cotton) from southern ports.
Let us assume your claim is accurate.
Tobacco and cotton dominated exports.
So? How did this constitute oppression of the South?