Maybe we disagree on what "fault" means; I think (and I'm pretty sure this is common usage) that if a person takes an action and a predictable bad outcome ensues, that person's at fault. It doesn't make him or her a bad person.

One last example: if you leave the laptop on an open windowsill and it falls out and breaks, is it now gravity's fault? If I throw it up in the air and fail to catch it, am I at fault, or is gravity? If I throw it and want the laptop to break so I don't catch it? Does it really depend on whether I want the laptop to break or not? What if I'm unsure of my motivations?

edit: I hope it's obvious, but multiple people can be "at fault" and the person who stole the bitcoins is more "at fault" than the victim here.