I'm sorry that you had such a bad impression of Amazon, but honestly, you only have yourself to blame for not standing up for yourself. You want to blacklist an entire company of 10,000 engineers just because you had a bad experience? I'll try to give the same interns at least some (hopefully) balanced advice:
The great thing about internships at Amazon is that you spend a full 12 weeks working directly with the team that you most likely will come back to if you do get a full time offer. I am not going to act like every team is completely wonderful, but you should know 100% of what your team does by the end of your internship. During standup, does the oncall say they spent the entire night working on an issue? Don't go back to that team! Are they working weekends? Ditto! I remember when I was an intern, our team had a huge project that was approaching it's deadline (oh also, any hardware release dates like the fire phone and Kindle have hard, set in stone deadlines, so it may be more stressful there). Our manager rounded everybody up, and he made sure that no more than a third of the team was working each Saturday, giving them two full weeks off. And the second the project was released, the schedule went back to normal. You should find out pretty quickly whether this is a team you want to work for. The team should be interviewing to get you to come back just as hard as you are interviewing for the team during your internship.
The whole stock/signing bonus crap? Yeah, don't take your first 15k signing bonus and piss it away immediately. That should just be a general personal wealth tip right there. With your considerable salary it's not like you need to spend it right away. The 'average Amazon employee also leaves in less than two years' is also a bullshit statistic. People like to cite the fact that the median engineer has only been around for about 14 months, but that is due to the fact that every year Amazon is increasing hiring by 40-50%.
Finally, there is this quote from OP: "Two years is also the amount of time you have to get promoted from Software Development Engineer 1 to Software Development Engineer 2 before they put you on a PIP and kick your ass out the door. If you are an SDE-1 at Amazon your job is in every way temporary, you are basically participating in a two year job interview for an SDE-2 role."
He is 100% correct on this front. Since all of you are just graduating college, we are willing to accept the fact that you are going to have gaps in your ability. You are going to need help. And that's fine. But if in two years, you haven't shown an ability to grow, an ability to keep learning even after being out of school, then you are going to not have trouble just at Amazon, but at any tech company, since you always need to evolve with emerging technologies. This whole promotion thing did cause me a decent amount of stress my first two years, but I talked to my manager and got constant feedback on how I can improve. That is what you should be doing as well. Oh, and although you may see it as a 2 year interview, Amazon is still going to end up paying you ~225k during it:P
I do agree with OP on one part: "Don't let them take advantage of you." And this advice is going to be great no matter where you work. Because at the end of the day, if you keep saying, "yes sir, I will be glad to do that, sir" they will just keep asking for more and more. A lot of people say that standing up for yourself could cost you your job. Luckily, if you've been hired by Amazon, you're one of the most sought after assets in the most in-demand field today. Having Amazon on your resume punches your ticket to any other tech firm outside the Big 5, and for those five it's still a huge plus. Your happiness is in your control. Talk to other interns around the company, see what teams they are on and how they enjoy it. Talk to other full-time employees, most of us will give it you straight about whether they enjoy the job or not. Amazon can be a fantastic place to work, but you will need to work a little bit at it to get the career that you want. Feel free to PM me if you have any other questions.