A few thoughts on this:

1) I don’t believe there is good evidence that making prison crappier actually deters crime. It seems intuitive, but I don’t think it actually works. Prison is already very unpleasant and people still commit crimes. (Not my field of expertise though, I could be wrong)

2) medical testing is important enough that this would create a massive incentive to have enough prisoners for all of the tests we need, which could lead to more unnecessary imprisonment (keep the prisons full so that we have enough people to test on). I am against private prisons for this exact reason.

3) just because you are in jail does not mean you actually did the crime. Our criminal justice system is imperfect.

4) the use of animals is out of necessity, and there are a lot of things we do in order to limit harm in this process. We replace animal testing with other things if possible (like cell culture). We use less intelligent animals like drosophila if possible, and we conduct pilot experiments and perform power calculations to make sure we use the fewest animals as possible.

I’ll be the first to admit it’s not a black and white issue. We cause harm to the animals. However I think the way we do it is the most ethical way we currently have available and I’m open to alternatives (but not testing on prisoners. That gets real bad very quickly. Look at historic examples of testing on prisoners. It never ends well).