My point is that IF they delete everything, they should send a notification to the affected users. When the repository is made public again, then since they deleted the star relation it’s not possible to send another notification.
That’s why I wrote “IF they delete everything”. You’re saying they shouldn’t delete everything, which I agree with, but that’s not the case I was addressing.
I’d argue that GitHub should send them a notification that the repo they starred has been made private.