Fred Clark (Slacktivist) connects the dots between crimes abroad and the war zones we build at home, where we don't need to have prisoners abused by insane Marines or deport them to Syrian dungeons—we can just let other prisoners do it:
If I had a dollar for every time I heard jokey remarks about how some sleazy guy will get what he deserves when he meets his new cellmate Butch, etc., I'd have a lot of vomit-covered dollars.
Some things are wrong because they're wrong, but a pure utilitarian who doesn't agree about the moral part might have an argument why they're OK. But some things are just wrong even if you look at them with your most cynical eye—they just don't even achieve the goals you might say you want—so the people who keep defending them are being driven by something actively sick, not just a lack of scruples.
The whole "is torture worth it" thing is like that: someone says "But what if it's a bad guy and you really need information because Jack Bauer has to find the bomb in 20 minutes"; someone else points out that when you torture people they'll say all kinds of things, and you'll never sort out the truth in a short time; and the response is something like "Well it must be effective because otherwise why is it so popular" or "It's worth maiming 1000 guys if it has even a 0.01% chance of working" or "I suppose you have a better idea?" The defensiveness, against even the most value-free facts, is so consistent that it shows they didn't try to think of something that would work and picked this; they picked this and wanted it to be OK, somehow, because otherwise we'll all have a lot of explaining to do.
The "if you don't want to get raped, don't go to prison" thing is the same. You can say that it's not just thugs and child molesters that this happens to; "Yeah, but if everyone just obeyed the law they'd have nothing to worry about." You can say that some people are falsely convicted, or did things less serious than many of us get away with; "Yeah, but it's still good for people to be really afraid of jail." You can say that this happens to women too and no one thinks that's OK; "Yeah, well then get better guards for the women, but men are just animals." You can say that people do eventually get released and they'll bring rage and diseases back with them; "Yeah, but that's why we should just throw away the key." And you can even point out that if everyone knows a prison sentence isn't just being locked up but may include beating and violation and AIDS and death, some criminals will be less likely to get locked up when they should be because we're not really sure they deserve all that; I guess the answer to that one would just be to lock up everyone. A commenter to Fred's post, Rebecca, said it better:
"The more horrible prison becomes, the greater the barrier against accusing and convicting the respectable; while the easier it becomes to put away those against whom one is prejudiced. For instance, it works against molestation *victims* twice— once by putting an appalling moral burden on them; and again by making everyone much less likely to believe them (because of that same burden.)"
I think all the evasiveness about this isn't because people are really comfortable with having millions of people in hell-pits; but no one wants to look soft, or no one wants to be the only one who's not laughing, or no one wants to think about having millions of people in hell-pits because it's scary. Or maybe they think we can concentrate all the horror into one place, so no matter how unjust it is, somehow we won't have any horror left on the outside. Or—if you think the whole system is awful and corrupt—you might think the more visibly awful we let it get, the sooner it'll all fall down... even though there's no evidence that anything has ever worked that way.
Anyway, what can we do? We can stop laughing at those stupid jokes, that would be a start. And check out these guys, who know what they're talking about way too well; they actually got Congress and Bush to take this seriously four years ago, but that doesn't mean anything will happen unless people visibly give a shit. More generally, the American Friends Service Committee does a lot of prison work, and tries to get people to see prison as a real place with people in it who still have some connection to life, not some kind of metaphysical garbage dimension.