It's obviously my own fault for expecting people to be able to do their jobs
I just had another run-in of exactly the same type with the same attitude that reverses roles -- the one who was wronged is labeled the aggressor, and the one who messed someone else up by his/her negligence becomes the innocent victim. Sick, sick, sick! It would be akin to someone knocking you over while he pushes past you and then saying you had no right to shout at him when he continued on his way without even an "excuse me." Further, he would say that you had no right to upset him because it was only an accident. Right, it's easy to say that when you don't feel the pain you caused.
Even if it was not intentional, the person still is liable. That's why we have damage and malpractice suits. Do you think the doctor really intends to kill his patient? Generally, not, but mistakes do happen with devastating consequences, and the victims want some form of redress.