Well they don't say they didn't read the thing. But 10-20 minutes often isn't enough time to truly digest the arguments. And even it were, I'm not sure it would matter. What I've seen is 10-20 minutes of awkward silent time followed by a level of discussion that isn't notably better than meetings before we adopted Amazon ways. Probably we are doing it wrong and/or have the wrong people in the room.

10-20 minutes seems short. Most doc reads I’ve been in at Amazon have a 30-40 minute reading phase. 10-20 minute reads would only be for very short or simple documents.