I've never worked at Amazon, but I've heard this a lot, and it always strikes me as an odd practice. Odder still is that it apparently works and everyone I hear talk about it seems to love it.
You're squandering precious meeting time by having everyone sit and read a document together. They could easily do the same thing ahead of the meeting, and you'd have much shorter meetings.
And doing it synchronously means everyone either sits idle until the slowest reader is ready or not everyone gets to finish in time. And "slowest reader" isn't even just about reading speed. Presumably, some people can understand the document more quickly because they have more context.
In design reviews at Google, it was obvious that the majority of attendees came unprepared and were reading the docs for the first time while their teammates were discussing the doc. I suspect that the reason was that Google just didn't have a strong docs culture, and leads/managers quietly tolerated people coming unprepared (and sometimes, they themselves were unprepared).
I've never seen it done in practice, but I don't think it would be hard to have the best of both worlds where people review docs ahead of the review meeting, but there are strong cultural norms around reading docs ahead of time so the meeting is just for discussion, not just for reading or pretending that you've read.