Trying to vilify people and attempting to create an environment to produce massive punitive damages and lawsuits, or to bring political pressure to change staffing decisions dramatically decreases safety. The FAA has spent almost a hundred years building up an environment of cooperation with a shared responsibility to understand failures and enable the changing of the entire aviation industry whenever necessary to promote safety. This has been fabulously successful.
346 dead passengers is definitely not successful or acceptable. You think the rating/MCAS problem doesn't merit further investigation?