Earlier quoted context omitted.
This is true as long as you trust the issuer of the transparency log to not go back and re-write the history of the log. That's a trust assumption that most folks are fine with, but it should be explicitly be understood to be there. A blockchain takes that trust assumption and spreads it out amongst the social consensus of the chain, so re-witing of history could only occur if there is a consensus to do so.
Who is both internal enough to get a copy of your HR database but external enough that their logs can't be changed as easily as a non-blockchain system's?
Send me a hash as new data is added to your DB and I cut you a cert... the next cert includes hash of the last cert plus the new hash you just gave me...