I'm a software engineer at Amazon in Retail. (This is just my opinion, I don't speak for Amazon in any official capacity, etc.)
Different software products have different severity levels. For my team, the oncall burden is not so bad. We have an internally facing tool. When we do get paged, it's usually requires acknowledging a ticket, a few minutes to validate something, sending an email out, and that's it. For teams with more externally visible products, a particular page can be stressful, but my understanding is they also spend a lot of time in ensuring system robustness in order to limit the number of pages. The "15 minute" response time the post referred to is generally to acknowledgement - the expected time to resolution can be quite variable.
The working hours are generally pretty good as well. The general expectation is that you're not working crazy hours.
I've ran into "project crunch time" at Amazon, but the experience at Amazon was like everywhere else I've worked. This also will vary by team: teams that need to make changes to support Black Friday obviously have a pretty hard deadline. Or if your team is getting ready for a re:invent announcement, there's no way to work around that. But from what I've heard, teams that have such a hard deadline also have a corresponding quiet period in December or January.
Most people I know within Amazon that get burned out on one team and feel like there's no resolution within that team (or just feel like they've had enough with one area) solve that by switching teams. This is generally pretty easy, since most teams are hiring at any time, and they would rather take an internal transfer than an outside hire.
Amazon has a pretty good system around having a senior individual contributor track (I haven't worked for any of the other big tech companies, my understanding is that they're similar). Part of the benefit of this system is that SDE1's/SDE2's have someone to reach out to for helping navigate management. Anyone at Amazon who reads this who is experiencing something similar to the OP should feel free to reach out to one of the senior engineers for help.
Overall, I don't doubt that the post in the original article is that person's experience, but it has not been my experience.