Why does American society blame victims?

[suplex3000]

It seems like worth major problems, we blame the victim,instead of whoever committed the crime. For example, in my town, when rape happens it's always, (if she didn't dress that way it would have not happen, or if she would have used the buddy system, if she would would have used pepper spray, etc). Instead of that, why not focus on the one who did it, not the victim. Or of someone is shot, it's "if they dress different, if they didn't park there, it wouldn't have happen" or they were in the wrong spot, etc. It's poor rationality!