Its ironic.
They enlisted in the Confederate Army to fight for the freedom to own slaves, although so few of them could ever realistically expect to own any.
They are now being enlisted to fight in the new Civil War, by plutocrats (many of them Yankees)to fight for the freedom to own businesses and exploit their own workers--although so few of them can ever realistically expect to.
And deep down inside, I think they partially suspect this. That's why they are so angry.