There are teams at Amazon full of some of the best technical and professional managers on the planet. There are teams at Amazon that are so brutally driven that they will sacrifice anything, even accepting an incomplete pentest audit and a forgoing week's worth of sleep, to hit a launch date.
I personally had a close friend on my team get PIPed and it was obviously a play from management to get rid of him. I have another friend who had to take months off after leaving because of the abuse she experienced. I have other close friends who have stayed for years.
It's such a big organization and the leadership chains are so decentralized that you get a wide variety of emergent patterns, and the decentralization makes it hard for people across the organization to know about the experiences of other teams.
Edit: in general I wouldn't say the horror stories are the norm at all from what I've seen.
Big companies are often far less consistent across teams than you'd expect/they'd like it to be, for better or worse
Once I came in to work in the evening, I had forgotten to bring my phone with me. There I find one of my coworkers crying his heart out because the women treat him like shit. I had not noticed a thing until then. They thought he was sent there to optimize them away and was making his life hell. He had sold his appartment and moved to our little town to work but couldn't take it and moved back again.
The company is the same for everyone (ie un-humanistic in its management), and if and when your personal circumstances change, you'd then perhaps see what others currently in it are moaning about.