It's evidence he's an asshole. And that's about it. Sociopath get's thrown around a lot, but it's a specific mental disorder that Bezos probably doesn't have at all. It doesn't just mean "Person is evil". Most of the nazis, for example, weren't sociopaths. Same with the people who participated in Stalin's purges.
For him to be a sociopath would imply a total inability to connect to another human being at a certain level, basically a complete lack of empathy for anybody. In contrast, lesser to no empathy for people you don't personally know, especially when conveyed as statistics, is typical across all of humanity.
Given he was able to get married and had a decently long relationship that didn't seem abused filled, he's probably not a sociopath.
And for the way Amazon works, from the link? Yeah, that sounds fine to me. This is stuff happening to white collar workers who are being paid above market rates to get as much out of them as possible. They know the stress going in, Amazon doesn't hide that. Netflix does a similar thing where it constantly fires the bottom 10% of workers pretty regularly. People signed up for the job knowing the hardship, and decided to stay there. They had plenty of other options, but chose the high stress, high reward one.
