I've heard there are huge communication issues within teams, thanks to policies like this. You have to look out for yourself first and foremost, otherwise you are up next for the stack ranking. Better to sabotage your team mate's onboarding than risk being next in line for the firing squad.

It's actually worse, because it's actually a "unregretted attrition" (URA) quota - which Amazon HR has spent decades developing into a sinister fear-based culture. They have a secret "FOCUS list" (used to be called devlist) which managers don't even tell their directs they are on. A secret list which if employees leave while they are on it (and remember, they don't even know they are on it), they are marked as URA and cannot be re-hired. HR directs managers explicitly not to tell employees they are on this list. Many employees only find out once they try to switch teams and are blocked due to being on these secret lists.

It fosters a culture of fear, uncertainty, and doubt - combine that with overly political managers fighting for their own lives, and Amazon can be a brutal place to work. The best teams are those that shield you from all these politics, but when push comes to shove managers are forced to make these URA decisions constantly.

Bezos believed his employees were inherently lazy and needed these types of mechanisms to scare them into doing their best work. Now that Amazon is the size it is, you can find crazy and absurd anecdotes of these policies being twisted into some truly bizarre Kafkaesque situations - like managers hiring individuals solely to fill the URA quota, and team members sabotaging onboarding on new members to try to avoid the firing squads themselves.