Wife and i visited Andersonville last year.
My oh my what a horrible history the place has.
I will say the Union POW camps were no better.
Neither side would muster the funds needed to properly care for the other sides prisoners.
You are correct. The treatment of Union and Confederate prisoners of war was deplorable on both sides. In the case of the Confederacy, by 1864, all resources were becoming scarce. What resources were available went to support the fighting armies. The Union, with considerably more resources, simply mismanaged the entire prison issue. They were capable of providing adequate food, clothing, and facilities but failed to do so.