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.
I’d read that there was harsh debate in congress which refused funds for prisoner care too
Wife is from New Jersey and had not been aware of these places