Imagine someone pricking you with a pin. And doing it repeatedly. For years. The crime is tiny, but you'd anyway want him to stop permanently.

So the question is what do we do with people who commit small crimes as a lifestyle, and have proven repeatedly in practice that our rehabilitation doesn't work on them? On one hand, harsh punishment doesn't fit the crime, but on the other hand, allowing to continue to offend all the time (we locally had an underaged teenager that was caught stealing 20+ times in less than a year, but was always released because the legislation doesn't expect imprisonment in such cases) is stupid as well, since it hurts victims.

What should we do with such people? I've no idea. Exile from society seems somehow appropriate, but we can't do that.