This is revisionist, false, and stinks of the DotC.
The war was about the South keeping it’s slaves, and it’s ability to continue to subjugate an entire race of people. The Declaration of Causes of Seceding States states that “our position is thoroughly identified with the institution of slavery.” That only the “black race” is capable of being slaves. And in case you think this could be twisted somehow to support a rally against taxes, it goes on to say “There was no choice left us but submission to the mandates of abolition, or a dissolution of the Union”
This is the opening volley off secession. It talks about commerce but not about taxes. It doesn’t mention counting slaves as votes because they’d won that fight 60 years previously.