Would you rather have citizens pay for it? I wouldn't, even though it's currently part of our taxes no matter what. It's perfectly logical they pay a part of their expenses, after all.
Yes, they paid when they paid their taxes before being incarcerated.
Otherwise, yes I want taxes to cover that. Just like I want taxes to cover healthcare. Without going into the morality of it, the whole point of this is pure practicality.
To lessen the risk on each individual, and distribute the load across everyone that's part of society.
That's if we want to have a society. If we don't, and we want true individuality, then we better also disband the army and the fire-department and the police. And have everyone truly be responsible for their own survival.
But no, when we think prison won't affect us (I'll never end up there; I'm a good person), it's very easy to not care about it. When it's something we could be affected by (fires/crime/etc), then we suddenly care and want societal level protection.
And all of this is without even going into the topic of how broken the justice system is. And how corrupt. How it all revolves around money and influence. And how many cases of wrongful incarceration. Or cases of incarceration for the most benign of "crimes". The one type of case I keep hearing about is incarceration for light-drugs, like weed. But even if it's serious drugs, the solution is not prison, but rehab.
All of this is to answer the question, how do we want to handle cases. As a society? Or as individuals? And most of the time it's funny how when it's something that might directly affect us, we want it solved systemically. But when we think it won't, we're happy to say that lone individual is solely responsible for his case.
When we'll have a perfect society on all other levels, then I'll be fine with pure individual responsibility when one person goes outside of the law.
As long as we don't have that, I'm not ok with blaming just the individual.
I seriously doubt slave labour is the norm, but I suppose it depends on the country and the prison. It's part of the sentence, and I suppose it pays another small part of their expenses.
Yes, it depends on the country. And from what I've read the US is probably among the worst.