Can’t comment on most of your post but I know a lot of Amazon engineers who think of the CoE process (Correction of Error, what other companies would call a postmortem) as punitive
They aren't meant to be, but shitty teams are shitty. You can also create a COE and assign it to another team. When I was at AWS, I had a few COEs assigned to me by disgruntled teams just trying to make me suffer and I told them to pound sand. For my own team, I wrote COEs quite often and found it to be a really great process for surfacing systemic issues with our management chain and making real improvements, but it needs to be used correctly.
Absolutely! Anecdotally, out of all the teams I interacted with in seven years at AWS across multiple arms of the company, I saw only a handful of bad teams. But like online reviews, the unhappy people are typically the loudest. I'm happy they are though, it's always important to push to be better, but I don't believe that AWS is the hellish place to work that HN discourse would lead many to believe.