As always, a public poll. Please give reasons for your answer.
A woman brutally murders a man's family or some other heineous act. In retaliation, he savagely rapes her.
Is this form of vengeance justified?
Revenge is an emotion, this means it's never a rational response, so your question is not scientific because it requires hate and emotional decision making, basically defeating the purpose of inquiry of this sort.
Rape is a form of torture, not a form of revenge. Why don't you explain to me exactly, what is the purpose of revenge? Besides a good feeling, what do you gain from revenge? How is revenge rational if it makes no sense other than to those who are naturally emotional and vengeful?
Now, if someone murders your family, torturing her is not going to bring your family back, and about the worst thing you can do to her is kill her, and that only damages her family, which does not bring your family back and which makes you as bad as her. So ultimately, put her in a hole, lock it, and throw away the key. We have prisons to protect us from this sort of behavior.
Basically, there is no reason to torture people, it's never a rational decision, you don't gain anything from it, you can do it and all it does is gives them pain, if you are a sadist maybe their pain is your pleasure, but it does not change the fact that the act serves no rational purpose that I know of.