"A big share of the revenue – as much as 96 percent — then goes back to the prisons, through fees due from these firms. In part, this money helps to offset the security costs to wardens of providing phone calls to inmates, ranging from call monitoring to providing escorts for repairmen. Much, however, is typically used to fund general prison operations and programs."So clearly all of the costs inherent in a prison phone system, including the added security required, is being covered and there's still a large amount of money left over that is being diverted by the prisons into other uses, essentially boosting the prison budget on the backs of the prisoners.
Look up offset in the dictionary. It doesn’t mean all. Part of the money is used to pay part of the added costs of the phone calls. Part of the money pays part of other prison related costs. In other words, the monies are mingled.
The article doesn’t state whether the money charged for phone calls is greater than, equal to, or less than the costs. In all likelihood, it’s about equal.
All of the money goes toward running the prison, which just happens to house the prisoners. So I’m still not feeling any pity for the criminals, and I still don’t think the taxpayers and/or paying telephone customers should have to subsidize phone calls and/or other luxuries for criminals.