My work life balance is good. My manager is supportive of me and my org takes mental health seriously. We don't hire to fire; in fact we can't hire enough people to keep up with customer demand.
Amazon is a huuuuge place with many different orgs. Maybe you can get stuck on a bad team in a unsupportive org. But to say every org operates as the OP alleges is simply not true.
I'm sorry they had a bad experience at Amazon. But their experience is in no way indicative of every org as they allege.
Also, I find it somewhat interesting that everyone who leaves Amazon after a negative experience blames URA and interoffice politics. It's almost as if it's never the person's fault they got fired.