When one uses the Templates chooser (New From Template), at the bottom of each template description is a blue link to a folder in Developer/Library/Quartz Composer/Examples. Clicking this link opens up a Finder folder that contains examples corresponding to the template (also known as protocol) type... in most situations.
The exceptions to this are "Basic Composition" (which is intended as a starting point, with a solid color, and has no "link"), as well as RSS Visualizer and Mesh Filter.
The problem is that RSS Visualizer and Mesh Filter entries both feature "links", but don't trigger Finder to open up corresponding folders that feature compositions of that type. While reporting the bug, the reason occurred to me; it wasn't a problem with the actual links, it's that needed folders don't exist in the Developer folder at all.
So, if one goes into Developer/Library/Quartz Composer/Examples and creates two new folders, titled "Mesh Filters" and "RSS Visualizers", clicking on the corresponding links in the QC Template chooser will open up these newly created folders.
It makes some sense why this discrepancy has occurred. The Mesh Filters have ultimately been implemented in User Library. With the RSS Visualizer, there are some other decent examples made by Apple, but they are part of other projects, or the actual template itself.
If one wanted to create those folders, and put a few "go to" Mesh Filters or RSS Visualizer templates inside, it is totally feasible to do so and add (back?...not quite appropriate...) the same kind of function to the Template page that exists with the other Templates.
(This is pretty much a "bell and whistle" feature; I setup QC to "do nothing" at open, and hardly ever look at the Template interface.)