Twitter has this kind of problem with likes (or maybe they fixed this since I haven't been on there in a while).
When someone deactivates their account, you can see that you have X additional likes, but you can't access them. If that user reactivates their account, those likes suddenly show back up.
This could be a privacy issue if you've decided to remove likes for a certain categories of posts for whatever reason.
For GitHub, a couple other options I can think of would be to 1. show stars for private repos but only for the purpose of unstarring or 2. hide stars when a repo goes private and then give users an option to re-enable their star if a repo goes back to public. But these options are relatively complex, and I can see why GitHub would go with deletion.
When someone deactivates their account, you can see that you have X additional likes, but you can't access them. If that user reactivates their account, those likes suddenly show back up.
This could be a privacy issue if you've decided to remove likes for a certain categories of posts for whatever reason.
For GitHub, a couple other options I can think of would be to 1. show stars for private repos but only for the purpose of unstarring or 2. hide stars when a repo goes private and then give users an option to re-enable their star if a repo goes back to public. But these options are relatively complex, and I can see why GitHub would go with deletion.