When we moderate we can add more categories or remove categories. If there are more categories that you ever want added just put it in a comment for your map and we can add it. Two seems to be the average so that's what nic put on the submission page.
In this particular case though I added 'ancient' and 'amphitheatre' when I submitted the map and the automatic category algorithm added 'theater - misc'. When this map gets moderated (It hasn't at the time we wrote these comments) I would normally delete the 'theater - misc' since the 'theatre - amphitheatre' is more specific.