The novel Disgrace is centrally concerned with notions of trangression. Emotional boundaries are compromised in highly significant and even criminal ways, yet the perpetrators of the transgressions are not brought to justice in a formal way.
Guilt and isolation are the punishments suffered by the transgressors, even if that guilt is denied, much like the guilt and isolation of Roskolnikov in Dostoyevsky's Crime and Punishment.
David Lurie is punished for his transgression by exile, forced to face himself, his guilt and his failure to win over the much younger Melanie. His crime is one of disrespect, on a certain level, less violent than the rape his daughter suffers in the novel's second half, but with a similar dynamic relating to the breach of privacy.
The private and emotional life of Melanie is, by socially defined standards, closed to Lurie, yet he insists on entering that life. This, again, is not the same as the criminal assault on his daughter, but this transgression is related both thematically and literally to its criminal counterpart.
The outrage that Lurie experiences after his daughter's rape is connected to the disgrace of his dismissal from the university. Dignity plays a part in his suffering and outrage but is not part of the victim's emotional landscape.
What Lurie does not realize, especially at the beginning, is that justice does not exist in a traditional way in his society, or perhaps, does not exist at all for some.
The inability to protect his daughter is, arguably, part of his suffering and punishment for the transgressions committed earlier with Melanie.