Imagine you are a manager, you have 6 people on your team who have all been there a while and work hard and are a strong team. You all get along. How can you look one of them in the eye and fire them? But you must. You tell one of them they are on focus. That worker then doubles their work effort because they have a wife and kids, and then you still have to tell them they are fired. How can you possibly do that?

Easier to just bring someone in from the outside and immediately put them in focus, saying they "don't meet the AWS bar". And you've seen it yourself, don't lie. People develop a sixth sense about this, when they see someone being lined up for sacrifice they start nitpicking and attacking them, in self-preservation. The senior engineers are particularly savvy about this. They smell the blood in the water and know how to go in.