Oh god whats wrong with it. Here we go.
There's nothing inherently wrong with being of the opinion that people can take reasonable steps to defend themselves from harm, and most people naturally live their lives that way; we avoid walking through bad neighborhoods late at night because we are aware there is a greater chance of something bad happening there, for example. And, by the same logic, women can take steps to avoid situations that would be more likely to put them in harm's way; not walking through a bad neighborhood late at night completely wasted while dressed like a prostitute, for example. That's just common sense that virtually everyone employs on a daily basis.
However, as soon as you start saying that there are steps that people
should take to protect themselves, you're essentially placing some portion of blame on the victim, and that's where things fall apart. A young woman was taken advantage of at a party? Well young women should know better than to dress provocatively or go to parties with strangers or drink... Why? Why should a young woman have less expectation of safety at a party than anyone else? That doesn't make much sense. If she's a victim, it's 100% the perpetrator's fault, period. Sitting around nitpicking her fashion choice or drinking habits shifts blame away from the person who victimized her in the first place, and that's not a good thing to do. It's not a victim's fault that someone else acted like an asshole.
Let's say you're walking through a bad section of town. You know better, but you just need to duck through real quick to get to the subway station. Oh shit, that dude's got a gun. He demands you empty your pockets, and you do because you don't want to get shot. And he runs off laughing. The next day, the police call you up and say "hey, we caught this guy and he had your stuff on him, do you want to press charges?" Hell yes. You take him to court, you're testifying against him, and the attorney for the defense says "So where exactly did this take place? Pretty bad part of town, right? Well, walking through that neighborhood, you can pretty much expect to get robbed, right? You basically set yourself up to be victimized. Sounds like you pretty much deserved this."
Does that seem like a reasonable line of thinking to you? They've got the guy, he committed a crime, and they're focusing on where the crime took place as though that forgives the act? Who gives a shit where it happened? It's still a crime.
That's exactly the same as saying that how a woman dresses somehow has a bearing on whether or not she gets sexually assaulted. It's a pointless diversion that takes away from the fact that she should have a reasonable expectation of safety regardless of her outfit, or where she was, or how inebriated she was, or any other meaningless criteria. We need to focus on the people committing the crime, not how victims can keep from being victims in situations where they shouldn't have been victims in the first place.