It gets complicated sometimes. What if the mafia have repeatedly extorted money from a shop owner, and the government can prove it but the shop owner doesn't w

It gets complicated sometimes. What if the mafia have repeatedly extorted money from a shop owner, and the government can prove it but the shop owner doesn't want to press charges because he's worried of what the mafia will do to him? That's not an abstract hypothetical, that's how the mafia traditionally operated. In the case of rape, the traditional defense is to drag the woman's reputation through the mud. Often there is pressure from the woman's place of work, and she really can suffer retaliation if she pursues the case. There aren't really easy answers in these cases, and I don't mean to imply that there are. But a blanket, "don't prosecute unless the victim wants us to" policy provides a lot of incentives for the criminal to engage in victim intimidation.