I guess you have no common sense? If you know you could get robbed then do not take the risk, no you shouldn't get robbed, but the reality is you could as crime is a problem in a city, so if you have any intelligence at all you make an intelligent decision based on that. You aren't to blame, but you are stupid and naive.
What is the problem with blame? Are you not willing to accept your own mistakes is that why? If you go into the mountains and get killed you are fully to blame, the bear is just being a bear.
A thief is also just a thief, and whilst it is not all your fault for getting robbed, they exist so act accordingly.
On the subject of sexual assault, it is stupid to assume anyone wants to be sexually assaulted so that is a dumb argument to bring up, but if you have the knowledge that rapists exist and drunk men are asses and a tight dress would only bring their attention to you, then you can choose what to wear. It does not mean you are to blame, but be intelligent in the crappy world we live in.
You have to live in reality, not in the perfect world that doesn't exist.