My guess is it doesn't have much to do with code reviews and more to do with firing people for other reasons that are not legally allowed: older workers, wants

My guess is it doesn't have much to do with code reviews and more to do with firing people for other reasons that are not legally allowed: older workers, wants to work remotely, HAS to work remotely because they moved assuming "remote forever" was a promise, takes a lot of sick leave, currently on some kind of leave, no code to submit because a project is not yet at the coding stage, etc. Code review sounds like a good cover for firing SWEs.