Technically, “Starring Actor” is not the only metadata field like that which isn’t exposed in the UI - “Country” is the same.
For that matter, there are other, more abstract, metadata fields that also aren’t exposed: resolution, aspect ratio, video codec, audio codec, audio channels, etc. Though with those I’ll certainly accept the argument that they’re derived from inherent qualities of the actual media file in question and so it makes sense to not allow them to be modified. …Except that just this week there was a request to be able to modify the aspect ratio info since some straight disc rips of content will include the black letterboxing bars and those bars are present when Plex’s media analysis occurs, thus the aspect ratio reported can be different from what you actually see for the real video content itself. How’s that for muddling the waters? heh =)
Anyway, I can certainly understand a desire to be able to edit both “Starring Actor” and “Country” info, so I’d encourage you to ensure that it’s been requested in the stickied “Feature Requests” thread for the Plex Media Server.
