Having it sweep through the prison population culling 70-80% of the inmates would be the only positive I can see in the virus.
It won’t spread through a prison unless they leave ebola victims inside to die and bleed on everyone. As a similar example it didn’t spread through the West Point slum when they closed it off. So they reopened, went in and removed the victims. It is pretty easy to control with that single step.
While I understand the emotional hardness on the matter, the reality is something entirely different.