This doesn't surprise me at all... Just like bots in games. Selling a service that benefits another. Its shady, but definitely believable.
Also, what if this is an actual viable way to "market" for an open source project?
https://www.bleepingcomputer.com/news/security/over-31-million-fake-stars-on-github-projects-used-to-boost-rankings
Why a real person would star a project? When I star a project then my GitHub home is littered with activity from that project. I hate that, so I never star anything
you can turn off notifications from starred projects