To be fair, blameless postmortem is at most dubiously part of anyone's culture, except at the smallest scale. It's not something that comes naturally to humans, and I only know of a few cases where it's stable at any large scale. The US NTSB comes to mind, but I bet they have to fight everyone else's urge to play the blame game on every investigation.
That's true to some degree, but in general there is far more willingness to find the truth. And in some cases blame also should be assigned; "never assume blame" is just as foolish as "always assign blame". There's often a bit of tension there.
