Nothing "anti-South" about it, but certainly Howe's song puts the lie to our pro-Confederates' claim that Civil War was "not about slavery".
As for "religious war", well... people who are ignorant of the Bible sometimes claim it supports slavery.
It does not.
At most it tolerates slavery where lawful, but not for God's people.
That's what Exodus & Jeremiah 34 is all about.
Why did Judah fall to the Babylonians?
For the same reason the South fell to the United States.
Read it and weep.
The "song" does that? How does a song prove something?
"Maryland, my Maryland" says that Lincoln was a tyrant. Does that song prove he was a tyrant?
The Civil War was indirectly about slavery. Slaves produced the money that powered 3/4ths of the US Government at the time, including their subsidies paid to Northern "crony capitalist" businessmen who were getting government contracts to build stuff up there.
Slaves also produced the bulk of the trade with Europe, and so long as the New York/Washington cartel controlled that trade and got their vigorish out of it, they were content to keep slavery as a permanent institution, ala the Corwin Amendment.
The one thing the were not going to allow is for the South to trade directly with Europe, become more capitalized, and compete with their industries, as well as compete with them for the economies and political alliance of the western states.
Money and Power. It's always about money and power.