A few points come to mind:
There is no need to advertise externally if you want internal applications only.
For safety critical roles such as guard, driver etc. the individual still has to pass the psychometrics.
If you feel so strongly I would encourage you to email the recruitment team to relay your experience but keep emotions out of it. It’s ok to say you were disappointed as part of constructive feedback but if you say angry etc. you’re making a name for yourself in future.
It doesn't appear this was internal though - more a "family member of a colleague" situation. Sounds like it was an "entry-level" gateline/platform/customer assistance role.