Maybe inside the SV bubble Amazon is viewed as a career stepping stone or prestigious or whatever? I can't relate but I'm in this weird career niche where open source commits trump or entirely replace resume/cv so I don't claim to be thoroughly knowledgeable about what motivates others. Personally I'd rather deliver pizza than work for a company that exists on the back of a pool of exploited low-wage workers. YMMV.
I've worked in a pizza place and known other people who have worked for pizza places, and none of us described it like a prison or felt the need to piss in a bottle.
No, instead they have a dangerous business model where they force their drivers to get to a location in 30 minutes or less causing them to weave in and out of traffic and crash in hopes of getting a tip. Much better than bottle pissing.
Having a big-name company on your resume helps you get your foot in the door pretty much anywhere else. That's just the way it is.
You can use that to your advantage or not, but you won't be helping any low-wage workers by choosing to work at a small tech company over a famous one -- well, maybe you will if you pass on a job offer from Uber, but for the most part, tech companies pay low-level workers better than non-tech companies.
Amazon employees are literally pissing in bottles because they can't take bathroom breaks without getting fired. Several have been hospitalized or died from heat-related injuries. This isn't merely about pay.