I think we’re on the same page here, this works a bit like cascading style sheets, if that’s a useful comparison for you, I don’t know, but hopefully so. The project has some basic definitions for how the outline should by understood, based on the disposition of the outline, but we can come along as say this part off the tree over here should have a different default understanding of what these things are. Normally items at this level would be “subsections”, but in this area they are “glossary entry”.
In the Outliner it prints “Glossary Entry”, in light grey, because it is inheriting that definition from somewhere up the chain—might be the immediate parent, but it might be higher as well, each definition cascades downward indefinitely.
If when you looked at the menu it said “Glossary Entry” with a tick by it, then that would be a different declaration from what we have. That would be the result of you having come along and selected that item and manually changing it. It would at that point be full opacity and printed in Roman in the outliner, too.
So printing that in the contextual menu would be misleading, it would say the wrong thing. It’s structure based, and can be proven so by moving the “Glossary Entry” item to a different area of the tree and watching it turn into a “Sub-Section”.
So again, I think we are all on the same page with this so far. I’m just reiterating to make sure.
While in that contextual menu you will also note that it says more than just that, it prints “Structure-Based (from ‘Folder Name’)”. So now you know why it is what it is, and where that declaration is coming from.
Granted in your case you used a sentence for a heading, so it doesn’t have space to print all that and cuts it off, but that’s where that info would be given at any rate.