Toured Andersonville lately?
Yep.
How 'bout Point Lookout? Johnsons Island? Elmira? Castle Williams? Fort Lafayette? Fort Warren? Fort McHenry? Rock Island? Benton Barracks? Camp Morton? Camp Chase? Chase? Camp Randall? Camp Douglas? or Camp Butler?
The Confederacy lacked food and medicine thanks to union blockades and war against civilians, they were even willing to pay Lincoln in gold for medicine, and to simply release prisioners without exchange. The offers were refused. What was the Union excuse for all the Confederate POW deaths?
The guards at Andersonville died of malnutrition and disease in large numbers, just as the inmates did.
Simply put, Andersonville Prison was the fifth largest city in the South during its last year of existence and it was completely cut off from supplies.
The Confederacy did not voluntarily withhold food or medicine from its prisoners.