Comment #4 on issue 430 by [email protected]: Keyword visibility modifiers for resource files
http://code.google.com/p/robotframework/issues/detail?id=430
The rationale for blocking access is exactly same as rationale for blocking access to private variables in several programming languages -- to prevent user of the resource file from accidently using the resource file in an untintended way.
Regarding your statement about contacting author and ask making it public, the same can/should be done independent on whether Robot actually prevents usage or not.
If you ask me, clear prevention of access would be better, but some users might disagree. A middle road could be logging a warning for using keywords labeled as private.
