In response to the end of the article "it’s important to note that some of these issues exist on other version control system products." I actually have experience helping someone with an issue on BitBucket with PII data that you can't rotate.

Once we eliminated the references in the tree and all forks (they were all private thankfully), we reached out to BitBucket support, and they were able to garbage collect those commits, and purge them to the point where even knowing the git hashes they were not locatable directly.