Nah, I think both you, visceral instinct and lepidistimushitthatshardtoremember have valid arguments.
I think any idiot, whether a feminist or not, would agree that a woman walking in a dangerous city at night by herself dressed really scantily is asking for it. Even well covered up would be stupid, but the skankiness ups the stupidity meter a few notches. Bad people come out at night and beat up and rape people. Everyone knows that we still try to control and contain the violence, but we still accept the fact that dense cities can be dangerous at night.
The reason it's dangerous is because of violent people. People are all different shades of violent. Some are very violent, others are vanilla violent, not very violent and positively nonviolent. In places that are positively nonviolent, I don't think anyone would object to women skanking it up (except for the fact that some find it inherently objectionable) and it wouldn't be stupid for women to do to that because there's no threat.
Reverse the situation of the all skanked up woman. Instead this time, she's in a super safe place, like, say, her mother's womb. If she was raped there, it would be totally objectionable. Nobody besides Muslim men wouldn't feel bad for the woman. It's supposed to be a safe place. If you're not safe to slut it up there, where can you?
But most environments are neither highly violent nor highly nonviolent. It's hard to make the decision each time, and make the judgment each time "Oh, well, she shouldn't have been dressed like a skank. Stupid woman," or "That's horrible that it happened; she totally didn't deserve that." Each situation is different. Women should be able to dress like sluts, but they should know to do it in safe places. They should know they're increasing the inherent risks involved in skanking it up. It's a natural law.