If people die in an accident, blameless postmortem shouldn't be the answer but accountability. Otherwise events like the MCAS disaster would be just an "happy accident" with no one to blame.
In a lot of cases, this one being a particularly good example, nobody was particularly incompetent, negligent, malicious, or greedy. But the system as a whole lacked safeguards so that a single person's inconspicous mistake could cause a disaster, and overloaded that person's attention.
Sure, there's other cases where you can clearly identify negligence, malice, or greed of specific people as causes of the disaster. But there as well, holding those people accountable doesn't fix the system than incentivised the greed, doesn't prevent incompetent, malicious or negligent people from getting into positions where actions based on those traits cause disasters, and doesn't provide safeguards against such actions.
The deterrence value of holding individuals accountable for extremely rare events is approximately zero.
- the airlines who wanted a more fuel-efficient plane that should still have the same type certificate as the (at that time) 40+ year old Boeing 737
- Boeing management, who wanted to keep those airlines as customers
- Boeing engineering, who did what they did at the management's request
- the FAA, who failed to spot the issue
- the mechanics of the involved airlines, who dispatched the planes without working angle-of-attack sensors
- the airlines who ordered planes without the (optional) "angle-of-attack disagree" alert
- the pilots (just for the sake of completeness), who failed to notice the issue and either refuse to fly the plane or correct it in time to avoid the crash
Who do you want to single out here?
...it's the same aviation industry with the same approach to investigations outlined in the article that did, in fact, expose everything that you know about the 737 MAX's MCAS issues and led to their ultimate mitigation.
But it was. Boeing being allowed to self-certify their own aircraft was ultimately what allowed it to happen.