It's a totally different world inside a huge company like Microsoft, though. It's massive and its own little world. After working inside for a few years, you start thinking that it's "normal". You see projects start up and get shut down, you see people trying to get into the company, you see people trying to transfer to other teams within the company, you see people trying to leave the company, you see people in the same team for a decade or more, etc. Because of the scale of things, you sort of become numb to a lot of things you see, so I sort of "understand" if somebody just figured recruiting would sort out that someone wasn't the right "fit" for the company.
I don't think this kind of behavior is necessarily the right one, but it's the outcome of a large behemoth made up tens of thousands of people.