Living in a society that more or less supports punishment as an ethical imperative make a difference. I suspect that few think that punishment changes behavior for the better; but they believe in the wrath of God, on earth. Those kinds of societal beliefs can lead to electing politicians and chiefs of police and sheriffs who believe in punishment at almost any cost.
Another possibility is that those we elect do not have strong beliefs, but have a strong sense of personal liability, and therefore hire chiefs of police etc. who will be punitive, and adopt punitive policies.