The punishment is conditional. Not real unless someone breaks the law.
Causing fear is not indecent if it promotes fairness and decency. Fear in and by itself is a negative feeling, true; but in case of the law one does not fear it, it is only a language expression to convey, "I'd better not break" the law.
The expression "fear" in "fearing the law" is not to describe an actual fear. Much like "fearing God" is not to describe an actual fear of god; it describes an entity that potentially can harm you, should you go against its will. Law or god, the fear is not an active, stress-producing, negative feeling... it is an expression only, which has its classic meaning shifted.
It is the fear of law that is useful in social conduct. You were right, Walker, the punishment is indecent. That's why many advocate the non-punishment of criminals, but designing a method which makes criminal behaviour unattractive to those who are toying with the idea of committing what we deem crimes, yet does not punish the criminals.
The punishing arm of the law is a numbers game. I suspect for each person who goes to jail for murder, there are at least a million persons who would commit murder should the law not punish them for it later. To do indecent things to 1 person (who murdered and went to jail) is better than to do indecent things to 1 million people, who would become the murder victims of those who do not murder only because the law stops them.
Haha! You, careful reader, you.
I like that, actually. Very much. That someone pays attention when s/he reads. Very commendable.