He has a decade of industry experience, took a new-grad level because he figured he needed to get his foot in the door, and discovered that the promotions process doesn't take his prior experience into account; he might as well not have worked anywhere else at all.
The real issue he has with Amazon isn't that it's bureaucratic - that there's a form to fill out for promotion, or that a variety of senior people he needs approval from seem to be fuckwits. His issue is that he wasn't treated as a person. Meetings weren't about getting the benefit of his knowledge and experience, they were about getting people to figure out how to parrot the figures produced by internal monitoring and circumstances in ways which best fit the Amazon Leadership Principles. That ultimately makes people feel like robots, like cogs in the machine. It's deeply alienating and unsatisfying - nobody really wants to work in an environment like that.