Let me clarify a bit here, there was a flaw (the MCAS issue) the caused a crash and a lot of people died. Supposedly the issue was fixed and steps were taken to correct the culture problems that led to the MCAS issue in the first place. Politics are involved etc.

Now we see a second serious (the door plugs) issue and another undocumented "feature" (the cockpit door behavior). So not only were the culture issues not fixed, but we have more problems and the same class of problem in the same line of planes that we've already seen. That burns political capitol and public good will very fast, plus tends to piss off investigators...