Aunty,
It's only not legal because certain laws make it so. Revise the laws. My position has nothing to do with religion (Muslim comment) nor communism. The very basis of social function is security. Humans are social animals, but the number one reason for forming social units beyond a few friends and family is security. Society's number one function is security. It isn't the only reason for its existence, but it's the primary one. In order to promote security, society should focus on the social unit, not the disfunctional (criminal) unit. Criminal activity is a threat to security, so society owes it to itself to protect itself from criminal activity - by whatever measures it finds most effective and, here's the rub, socially acceptable.
My premise is that too many in society have come to not accept highly effective measures that promote security. (The philosophical correlary is that we've gotten what we deserve then.) However, I'm at ease with the notion of prisons being primitive storage grounds that have both harsh social and physical environment. There's nothing inherent in the social order about providing 3 hots and a cot, not to mention wall to wall carpeting and color TV, to those who have demonstrated they are a risk to security. It's within the scope of natural and logical consequences that those who violate society expose themselves to significant personal risk.
While there are many causes of crime, like disadvantaged social background, and lately even unemployment among educated and ambitious people, a continuing cause of crime is that crime pays. Well, it doesn't always exactly pay, but when you have to be convicted of stealing more than 6 cars to serve jail time, lack of adverse consequence is a form of payment, etc. And that is clear evidence of a society choosing not to protect itself, and therefore failing its fundamental role.
Salmo the liberal, but no bleeding heart