There are kinds of activity for which we not only have names for the activity, but also for the doer of the activity. Not only sculpting but sculptor; not only drinking but alcoholic; not only psychotherapy but psychotherapist. Clearly, when we refer to a person in this way, the implication is that the activity is part of that person’s identity and that they do it frequently and regularly.
As it happens, we also do this for crimes. We not only have names for crimes, but for “criminals.” We not only have theft, we have thief. We don’t only have murder, we have murderer. Not only rape but rapist. And notice that I placed “criminals” in quotation marks: we not only have crime, we have criminal. As before, the implication is that the person commits crime frequently and regularly and that crime is an inseparable part of that person.
Is this correct? For what number of those that we call “thieves” is thievery a part of their identity? How many of those that we refer to as “murderers” commit murder often and regularly? An extreme minority. Referring to a person that committed murder as a “murderer” is as correct as referring to me as an “astronomer” because I once looked through a telescope.
Why then do we do we refer to people that have broken the law in these terms? I believe the major reason is a desire to dehumanize in order to not understand: she did not commit rape because of a complex of causation leading to the event, or because of the situation in which she did it — rather, the act of rape revealed her true identity as a rapist. The causal explanation of guilt, which is difficult to understand, is substituted by the guilt itself, which is not an explanation at all and so is easy to understand.