That is not a mandatory part of using source control. Modern source control can work entirely on your own computer.
>Force push protection stops you from rewriting history
This doesn't always exist and usually there are ways to disable it.
It does sound right.
Obviously the world isn't black and white, and whether something is a backup depends on what threats you are backing up against. Backing up in case of disk failure looks different then if you want your backup to survive a nuclear war.
But ultimately yes, if you configure restic/borg to backup to a different directory on the same disk (and not even different access control), that is not a backup.
It has nothing to do with git. Making a copy on a separate server would still be a backup even if you weren't using git. Using git without pushing your repo somewhere else would not be a backup.
I agree source control is not backup, because it implies having `git` is enough. It's not. Example: an Agent or process deleting your .git folder doesn't protect your code.
At the end of the day we have a developer injecting malicious instructions into their project, with the openly stated goal of causing data deletion, and the people supporting that effort are doing so because of their personal ideology. We have laws against this for a good reason.