Why would they be less safe?

Private prisons save money by hiring fewer guards, paying them less, and giving them less training, as well as by providing fewer educational, medical, and enrichment services to inmates. The result is less control of the inmates and more violence. A scathing 2016 report by the Justice Department’s Office of the Inspector General found that federally contracted private prisons had more security violations per inmate than public prisons, including a 28 percent higher rate of inmate-on-inmate assaults and more than twice as many inmateon-staff assaults. In an attempt to regain control, private facilities threw more inmates in solitary and used prison-wide lockdowns more frequently.