Some percentage of muggings are less about the money, than in the sense of power over the victim.
In the case of rape, for some percentage the sense of power adds to the sexual excitement. If this was not the case, then paying for a prostitute would make more sense. Even committing robbery and then using the money to buy a hooker would generally involve less risk of jail time than violent rape.
Exactly..
It's SOME, not ALL.