As someone who runs a bunch of private repos on Github, and hires freelancers and vendors to work on them, I like the way Github manages forks of private repos. When I end a relationship, and remove that person from my private repo, I want their fork of my code to go away too.

Why? Because it's cleaner. It means there are no abandoned copies of my codebase sitting around forever forgotten in random Github accounts. I set up a private repo because I want to control access to my code. That's why a private repo is private.

It also makes it harder for people to misrepresent their relationship to me later on. Sure, anyone with read access to one of my repos can pull it down and save a local copy. But that is different from logging into Github and having a fork of my repo. A Github fork looks and works differently from a local copy.

This whole situation seems weird because the idea of a "private" repo is not inherent to how git was intended to work; it's something Github invented to make money. So I'm not surprised that it violates people's expectations sometimes.