Rape is a form of violence enacted upon the victim. That violent act is enabled by the rapists' mental condition. Mental illness can range from a need to control, inflict pain, inflict dishonor and not typically as an act to satisfy a sexual need. Indeed in some cases the sexual urge can be the driving force but it is typically secondary to mental illnesses. Some discussions list the following types of rapes; anger, power sadistic, gang and sexual satisfaction. Many convicted rapist interviewed indicates that anger rape to gain power over the woman is the primary logic for rape. Rapists typically have difficulty in forming social bonds that may lead to consentual sex, therefore, the rape.
In answer to your question, who is at fault? The rapist is at fault and the gender of the rapist may be male or female. In almost all societies the male rape victim typically will not report the rape and even some women are reluctant to report a rape due to the stigma associated with the act. However, the majorit of rapes are by men and due to that man's mental state, they are at fault by that fault may be enhanced by the mental illness that has not been treated. In some societies the act of rape is tolerated due to the low societal standing of the woman as well as beliefs that it was her fault because she dressed or acted in a way that provoked the rape. This attitude is flawed since a man without a desire to control or hurt a woman would not rape a woman. many factors are involved in one act and a simple answer or solution is not possible. Social, economic, religious, and medical factors all can play a role into this tragic act that can scar a person for life.