If I'm not mistaken privatize prisons only house about 10% of the imprisoned population and only account for a similar amount of the total expenditure on prisons. Their existence is concerning but I think something of a chimera with regards to the broader issue of imprisonment. At the same time it is indicative of the same creeping "MBA consciousness". IIRC total prison population is more like 2 million. If I'm not mistaken the use of inmate labor is likewise another overblown concern as far as its economic significance--while the surplus labor there is huge, it's a small portion of what goes on.
There's also the rents paid to vendors like Aramark for the 1400 calories a day they provide to prisoners.
I tend to think that practically opposing vastly-underpaid prisoner labor is a much easier target than the privatization of prisons, which at present isn't significant though it quite certainly could be.
-- Nathan