One of the main reasons to limit media access to prisons was the government didn't want prisoners reaping benefits from their crimes. When prisoners can glorify their crimes, it adds insult to the victims. I agree with that. However, when media access is controlled by prison administrators, abuse of prisoners and human rights violations often go unreported. Prison administrations are free to manipulate the media to cater to its agendas.
The public has a right to know what's going on inside of prisons, good or bad, when prisons get to controls the media, it's able to control public opinion.