Private prisons often appear so attractive to lawmakers because they claim they are able to save bundles of money compared to government-run prisons. While this isn't exactly the truth, these companies still routinely cut corners in almost every aspect of their operations in order to maximize profits, because, after all, that's what they really care about. Since staff expenses (salary, benefits, training) comprise the largest portion of any facility's budget, private prisons often pay dramatically less to their staff in the name of profit.
The problem with this approach lies in the fact that private prisons, because they offer less in salary and benefits, aren't able to attract as high-quality candidates as government-run prisons. Just recently, when Hernando County Florida took over operation of its jail from CCA, the sheriff hired only about 1/3 of the private company's employees to work for his department (and remarked at the time that he couldn't believe a lot of CCA's employees weren't incarcerated themselves). Anecdotally, it's rather well-known that many guards at private prisons have some unsavory histories, and guards who screw up at one prison or another (government-run or not) can usually find work at a different private prison, where the companies rarely perform background checks that are as extensive as the government would. Combine all this with the industry's aversion to providing adequate and consistent training to their guards (because, again, that would hurt the bottom line), and you've got a recipe for disaster.
Unfortunately, this disaster revealed itself to women who immigrated to the US but found themselves locked up in the Hutto Correctional Center, part of ICE's network in Texas, which is operated by CCA. A guard at the facility just pleaded guilty to sexually molesting immigrants as he transported them to and from the facility.