This may be nitpicking and I understand your overall point, but using but-for cause to establish culpability gets dicey IMO. Like, Pretti wouldn't have been killed if not for the woman he tried to help, so is she culpable? Would people have fallen in different ways if they were wearing different boots and clothes? To me, there's always a LONG list of "this wouldn't have happened if not for _______" and people often ignore 95% of them and choose one.
That's why the law generally prefers proximate cause. Again, not saying it changes anything about the example you gave, but people using the specific "wouldn't have happened but for _____" argument is a pet peeve of mine