I'm really not sure I buy that ... what about rapists during war, etc? In that case it seems to be more about humilation rather than wanting to have sex with someone. People who rape someone for bullying them at school, or because they remind them of their mothers, or got a promotion instead of them, or because they were late home from work and wouldn't do the washing up, because they are a "fat bitch", or because the victims are richer and drive an expensive car that the rapist would like to own, or because they are poorer and therefore the rapist looks down on them and thinks they are worthless "chavs", on and on and on. I'm sorry but these aren't anything to do with sex, maybe in a rapists' mind they could become equated with sex, but IMO it stems from things that are nothing to do with sex in the first place and more about the self esteem of the rapist and their feelings of entitlement/insecurity and a desire to control other people.