Turn it on its ear.
Supporting "private prisons" is supporting jail rape. You dont support rape, do you? Because private prisons like it when their inmates rape other inmates-- it increases their charges, meaning they will never leave, and the mental damage to the victim in an incarceration setting makes them more likely to commit additional felonies as well.
I don't, but I can tell you that a depressing number of people do. "If you don't want to do the time, don't do the crime", law-and-order types tend not to be too bothered by that sort of thing -- look at the cop who taunted a convicted young man with a tube of personal lubricant after he was sentenced.
Besides, there are ready-made justifications for this sort of thing. If you want a twisted message, "would you rather all those rapists be out raping innocent people" would work. They're terrible reasons, but people will use them to hide their own secret wish that all "those people" make each other suffer for being criminals and therefore worse people than they are.
In essence, I think you may be underestimating how terribly spiteful and bigoted people can be.
I never once thought you did-- it was an example counter-argument to the kind of shit I expect from "Fiscally motivated" mouthpieces in favor of private prisons.
I get that. My point was that arguments from prisoner well-being aren't going to fly with people who want prisoners to suffer, and that sentiment is so prevalent that the opposition to reducing prison rape might well be politically relevant, just coded in a way that lets them couch it in financial or judicial terms. It's simple to twist the statistics, too. Hand the bigots a line like "inmates are twenty-five times as likely to take part in unwanted sexual conduct as the general population" (carefully worded to include victims in those blocs) and they'll be adamant that those people, those others, stay behind bars where they can't get at them and theirs.
It is a sad world we live in, because this is indeed the truth ^^
About the only way out of that, is to have 10 second ads with short messages from "petty criminals" (EG, white collar types) who get violently raped in prison, contract HIV and worse from it, and have no out, and no public sympathy. Give that blind dehumanization a real human face. (as many as possible.) Preferably one that looks just like theirs.
Dunam'--
The "Not sustainable" cry is a half-truth. What they really mean is "Not sustainable at the current rate, and length of stay of incarceration."
That is to say, not sustainable when we throw 18 year olds in jail for having a nickle bag of pot, and other absurd offenses, tries as if they were columbian drug lords with a whole airplane full of vacuum packed weed.