If you're walking in a bad neighborhood at 3am and you get mugged, should you have chosen your path more wisely? Maybe. But would anybody say that _because you chose to walk in a bad neighborhood and you got mugged, the mugger isn't at fault and shouldn't be prosecuted for the crime they committed_?
No, probably not. Mugging is a crime, and just because you put yourself in a situation where you're more likely to get mugged doesn't make it less of one.
Why does the same not apply to sexual assault?