Unicor helps keep order in federal prisons which with ever increasing jail time mandatories is not easy
It also gives prisoners a little canteen money which is less cost for the state plus state earns from canteen...probably over one million per year in a big joint
And a little money prisoners can even send home for kids birthdays..quinces and bar mitzvahs
Caveat is it is indeed unfair competition with private sector
Remember the prisoner labor in GWTW.