The prisoners DID NOT have the emenities you mention. My ancestor spoke of men freezing to death, because they were not given blankets. Many of the men died of Typhoid fever.
The South did not even have the resources to feed the troops, much less prisoners.
It is a matter of public record, well-documented from adversarial newspapers at the time.
Journalists commented at the time that one stove for a barracks of 120 men was insufficient, that the infirmary facilities were too small, etc.
The amenities existed - they proved inadequate to the task.
My ancestor spoke of men freezing to death, because they were not given blankets.
There was one blanket for each. And that was simply not enough in a clapboard barracks in temperatures that got to 30 degrees below zero in the winter of 1863. I'm sure some men did freeze to death in those conditions.
Many of the men died of Typhoid fever.
Correct. That was the leading cause of mortality at Rock Island.
The South did not even have the resources to feed the troops, much less prisoners.
Ah, but the South did indeed have the resources. Confederate troops were living hand to mouth and Union prisoners were starved to death while the Southern civilian population outside of eastern Virginia was richly provisioned.
When Sherman's troops marched through Georgia in the winter of 1864, they found more beef, grain, textiles and hay than their 35,000 strong force could possibly use. And if you look at the map, Sherman's forces only covered a small fraction of the state of Georgia on their march. The troops' letters and the officer's reports are full of long lists of the provisions they took, many expressing surprise at the sheer bounty they found concealed all over the countryside.
One of the secrets of the Confederacy is how standoffish much of the population was to the war effort and how reluctant state governors were to requisition supplies for troops in forward areas.
Prisoners starved because of malfeasance and Confederate soldiers went hungry because of mismanagement.