The problem is not beheerder
One can argue about Google Translate and its relevance back then, or how the previous admin should have been a bit more knowledgeable, but the real problem has nothing to do with the admin name.
The real problem is that this Dirk launched a file operation without checking what he would be transferring. It's that second of inattention that always gets you, and it got him.
When you are the admin, you never initiate a file operation without checking and double-checking what you're doing. With your access, it's way too dangerous not to. He didn't check, and the mayhem lasted a month. I'm guessing that was a learning experience for him.