Because once published, you must stand by what you published. Accept your mistake. Put a big notice on it saying how sorry you are and how much more careful you will be in future. Hiding it is running from it.
> If it's better from the perspective of journalism, does that conflict with what's better from the perspective of not being sued?
It's all about how much these "journalists" respect their own profession. If I commit a horrible bug, I don't go and purge it from github using --force. I leave it there as a reminder and acceptance of my mistake.