Okay, So you have probably created that TheaterView Documentaries using Standard View as a template and in that Standard View you have at least had some grouping categories which TheaterView inherits but isn't visible anywhere in the TheaterView anymore! (which is peculiar but it seems that this is the way MC import views from standard view )
Anyway...
If you show that Standard View's "Customize View" rule so then we can see the category groups and can figure out that some of your files (the unassigned) doesn't have tag value for that field. I think that this is what is going on.
The tag your unassigned files is missing is the tag which has value eg "discovery channel documentaries", "National Geographics" etc on some files. Filling that would raise the video from that unassigned category