Let's get rid of poverty for everyone. No one deserves to live poor.
We should force the people who were super greedy and became dragons with hoards of cash to work for the public in a service job like janitor or old person care. Maybe that will make them think about other people.
Well, it isn't that punitive measures serve no purpose. They do. But that purpose doesn't decrease the chances of a given crime occurring by other people, nor does it prevent the same people repeating a crime. To the contrary, the way most prisons work, chances are that anyone going on comes out with less options, and more knowledge of crime, so even if they don't repeat the same offenses, they're put in position to do others out of necessity.
But it does seem to make people feel better when someone else gets punished for doing something wrong. Which, in theory, is going to reduce vigilantism and mob justice. In practice? I dunno, I haven't seen enough data to form an opinion about that specific matter.
Generally, the reason it shouldn't be the main goal of a justice system is lack of efficacy. It just doesn't do what people want it to do. So, what's the point of that?
If your goal is to reduce crime, and reduce recidivism, rehabilitation has shown to do a better job. Prisons should be the last resort for non violent crimes, not the first. Even then if prisons hope to do more than isolate repeat offenders, they would need to have more intensive measures to help people change.
The world has had punitive justice systems for hundreds of years. It doesn't work. The countries trying restorative and rehabilitative justice systems are seeing amazing results.
Because that empirically tends to negatively interfere with rehabilitative functions of justice. If crime is bad, preventing crime is good, and stopping crime prevention therefore is bad.
Because at first you have to find the cause of the behavior.
Punitive justice should be the last resort.
The problem, the moment justice has to work, a problem was not discovered and solved early enough.
I would say every government punishment is a prove about a community and government failure.
The moment justice step in you need to punish an incorrect behavior to prove that the rules that exist are valid and enforced. So one part of the punishment is not for the criminal it is for strengthen the existing rules.
In developed countries there should not only be the punishment but also an investigation how this could happen and some form of help to solve the issue. And additional punishment if other people where harmed.
Punishment is part of justice. Seeing that somebody who does wrong intentionally and with malice suffers, proportionally, is part of the lesson that the justice system teaches.
In my opinion, punishment is important for the victim (to see that they are protected, and to satiate any craving for extra judicial revenge), society at large (to demonstrate that there is a governing body that will not let people get away with causing harm), and for the criminal themselves (to show that harmful acts will result in reprisal).
It crucially can't be the whole lesson, though. There has to be guidance, forgiveness (on a legal level), and a corrective path available to people who hurt others. Punishment on its own often just perpetuates systems that produce criminality, and isn't enough to effectively reform people who have done wrong.
The higher question is why shouldn't society be punitive?
To start with prison/justice, rape/violence being a feature means gang support systems are a feature, and crime university is a feature. Police are empowered by being agents of punishment. Privatization of parts of justice system incentivize kickbacks for punishment, and school to prison pipeline for the structurally oppressed classes.
Structural oppression in society serves oligarchist low hanging fruit of wage suppression. Structural desperation that motivates gang/mafia membership and crime as alternate protection from a punitive society. Importantly, if society isn't hateful, corrupt, and punitive, then why the fuck would you care about a politician who champions putting bandaids on it to make society more hateful and divisive, even if their real agenda is more war and service to Israel? Late stage democracy ensures collapse for zionist oligarchist pillaging.
UBI/freedom dividends is the only democratic idealist function. Not political power. It eliminates structural crime and oppression. Liquid democracy with UBI eliminates corruption and dysfunctional policy. A functional improving sustainable society is impossible when hate is prioritized.