Hi @hexdump ,
Don’t worry about it, just Select and see what gets Selected.
What you are talking about are Boundary Edges (term from Mathematics, Topology). In Blender an Edge that connects to exactly 1 Face is a Boundary Edge. Selecting an Edge Loop from a Boundary Edge once gives the left result, ALT Selecting the same Edge again, Selects the whole Boundary as seen right::

But seriously, don’t worry about it, just accept what happens when Selecting Edge Loops.