Think of it from the point of view of the (often for-profit) prison: The less of a chance of re-integrating with society the inmate leaves with, the greater chance he'll be back, which means more $$$ for the prison.
"Broken down to prison type, 19.1% of the federal prison population in the United States is housed in private prisons and 6.8% of the U.S. state prison population is housed in private prisons."
Source: http://en.wikipedia.org/wiki/Private_prison#In_the_United_St...
