There's an extremely wide gamut of potential answers to this question. "Either we lock them up and throw away the key in a violent retributive system or we let them roam the streets free of all social constraint" is a false dilemma.

At any rate, it's not necessary to pick a specific answer from the massive pile of alternative approaches tried, theorized, and developed in modern history to say that this one thing that is done in the US right now is clearly not the right answer.