If I have a Markdown document called DocumentOne with three links to DocumentTwo, DocumentOne’s links inspector will show two outbound links to DocumentTwo.
DocumentTwo’s links inspector will show one incoming link from DocumentOne.
For my uses it would be a little nicer if the links were de-duplicated like the incoming links pane. Just a thought.
Why would they be de-duplicated when they point to specific pieces of content in the document?
Ok, I see - the outgoing links are themselves links to places in the document.
I didn’t realize that, but I’m glad to reaffirm my status as an end user. Cluelessness is essential in that role! 
Edited to add - the de-duplicated list of incoming links is still nice. I can click on one, command-R, then navigate its list of outbound links for specific references.
No worries!
Here’s how I see it…
“Here’s a link to document A, but also one in this other paragraph, and another in that last sentence.”
All are independent links (and potentially contexts), even if pointing to the same document, therefore reported independently.
“What documents are linking to me? Oh… those three documents are!”
Whether each document has one or one hundred links to a document, it’s still only necessary to know each one links to the current document.