A guess: You could be seeing a side effect of laws that require companies to remove all of a user’s “data” upon request.
They may have been legally obligated in some jurisdiction.
Unfortunately under these laws the issue isn’t yours or your projects. It was the users.
There are a lot of unintended side effects like this.
> This is concerning that in order to have a properly functioning open source hosting we would have to archive regularly.
This has been the case always. Remember when SourceForge would inject adware into the installers? It's just a fact that when you're using a thirdparty's server to host your stuff, you cannot completely control what you're hosting. You're at the mercy of the thirdparty.
It's no excuse for GitHub deleting something you took the time and effort to write and share with the world for free. But with enshittification and all, I don't know if we can ever expect fair treatment anymore.
For total control you're going to need to host stuff on your server or put everything like issues, pr comments, wiki into your Git repo. Fossil does it. But git doesn't, at least not yet.
Another GraphHopper dev here. This is quite odd. Github users should not be able to delete comments of others by simply deleting their account, even for issues they opened themselves.