I guess there are two aspects to prison: the first is as you said, a deterent, an agent of rehabilitation, a place of punishment, etc - the ideal form. Question

I guess there are two aspects to prison: the first is as you said, a deterent, an agent of rehabilitation, a place of punishment, etc - the ideal form. Questionable, but ultimately something a lot of people could agree to. Then, there is really-existing-prison, which is a place of misery for the people who, almost entirely due to structural reasons, get railroaded repeatedly into its embrace. So even prison abolitionists are often rather sanguine about imprisoning people like CEOs and high level officials who, despite being absolutely manifestly not railroaded, who have the structure covering from them at every turn, and end up both committing and being convicted as criminals. I don't think this is necessarily contradictory: you can be fine with the idea of some kind of prison while also recognizing that the current system is a rather pointless and dysfunctional form of sadism that has no relation to any practical or ethical goal.