To point out what might be obvious: this doesn't transfer _just_ the stars. It simply swaps two repos, which means the issue tracker, pull requests, watchers, forks, projects, etc., also get transferred with the stars.
It's not possible to transfer just the stars while maintaining all the things that you can't directly control.
I did something similar when I decided to change my github username without changing all the import paths of Go packages I had. I changed the username, made an organization with the same name as my previous username, then moved all my repos to the organization. So the URLs of all the repos stayed unchanged. [1]