They all are just rooms, offices or places in a companies or government offices.
I don’t think they need to be registered.
This is because those companies and government offices, or the buildings within them (some companies and government offices own multiple buildings on one site) are already registered.
There is no point in registering 10 or 20 places in a small building in Japan with the name of the department and sections.
Is it against Google Maps policy to delete these locations?
You found many same name place of Government department Right ? you should go to Places their which you found is duplicate of original place their is option on Suggestion then Click on that you will see Close this place then you will see why you want close or remove this account select Duplicate of another place then enter the Original place address Submit Done Internal team will check and if they found its correct they will remove these place from google