Hi there! Sorry I didn't get a chance to reply to this earlier.
So my basic response to that is "it depends". I have previously been in a different team at Amazon and that team definitely had much less room for slack. If you didn't push yourself hard, you probably couldn't get promoted there. But then again, they also had issues with attrition.
The culture in teams can vary quite a bit at Amazon. I think it mostly comes down to the leadership. More than any other "big company" I've seen, Amazon emphasizes ownership. As a VP (and even as a manager, though to a much lesser extent), you get nearly full freedom to define your team's culture and set the direction of your product. So yeah, I don't think every team has a great culture within Amazon; a lot of it depends on the culture defined by your leadership team.
In regards to your last point:
> "I'd be curious to know though, and be honest, you've really ever only worked 40h weeks? You havnt logged in on a weekend or an evening, stayed longer on an Thursday, checked your mails when off work? Not ever? Ignoring on call time offcourse."
Most weeks I probably put in a bit more than 40 hours. Maybe closer to 45 or 50 hours. That's the average. Have I put in more occasionally? Of course. Do I sometimes check emails on a weekends or evenings? Yep, of course. But there have also been times when I've come to work at noon or left by 2pm if I needed to do something else. And, 90% of the time, I don't respond to emails outside of work hours. That doesn't feel very much like a "sweatshop" to me.
I've worked at other companies besides Amazon and I have plenty of friends who work at Google, Facebook, Microsoft, and Apple. My friends at Microsoft will often put in 50 to 60 hours during a live site outage or near a product release. I have friends at Google who check their email on evenings and weekends. One of my best friends is at Facebook and does the same. I know less about Apple, but I've heard their culture is pretty intense. So, in that sense, I don't feel my team's work culture is any worse.
Overall, I like my team and I think that credit goes upwards through my management chain. Good managers make a huge difference. Perhaps Amazon needs to do a better job in ensuring teams are more consistent in creating a good culture across the company.