Personally, I worked at two companies before Amazon.
I left both companies because I was unhappy. Two people from my last company also left for the same reasons I did. One of them is at Amazon, and the other one is at SalesForce.
Does my experience at my last employer represent a systemic problem in their work force? Probably not. I did know folks who were plenty satisfied and didn't leave, who didn't follow me even after I tried to recruit them.
All I'm saying is – it's easy to draw a conclusion and the wrong one. When you have a company that hires at Amazon scale, 1% of your workforce being unsatisfied and some percentage of that 1% willing to speak out about it means you have a lot of negative press. At that point, your rival companies, especially in the news media, have plenty of ammunition to run campaigns where that 1% seems like it's 80% or 99%.
Lastly – there is a negative Amazon article on HN just about every single day, and from reading those articles, it seems like people out there wish my mental was suffering or I hate d my job, even if I feel great and like the people I work with.