Here's my perspective:
If a person walks down a dark alleyway in a violent neighborhood in the middle of the night and gets assaulted, the assailant is 100% responsible for the damage that was done. But the victim bears responsibility for knowingly putting themselves at risk, or for being ignorant of the conditions to begin with. But WE (that is, the rest of us who are neither victim nor perpetrator in this situation) don't need to hold them responsible. They will bear the consequences of those actions regardless of whether the assailant is brought to justice.
Our (that is, society's) responsibility is to identify dangerous alleys, enact legislation to make them less dangerous, and educate our citizens about the realities of how to protect themselves from being a victim. Because we don't live in a world where everyone acts with 100% pure, ethical, and just intentions.