Hi @mlavengood,
The answer that @ProfessorBeyrer gave does provide an accurate description of how Cavas currently functions. There is not a way ro exclude particular courses form the to-do list right now, but if this were submissted as an official idea, it may be considered in the future.
As a Canvas admin for my institution, I can say we have put a lot of thought over the years about what should be in Canvas and what should not, much of the disucssion happening aorund things like this. Canvas is really first and foremost a learning management system to allow students to complete courses digially. Canvas is flexible in that it could also be used for professional development training for teachers, for student groups/clubs, other academic centers, etc, but sometimes it may be better to house some of those extra things in a different system to avoid blending of academic content and noo-academic (like is highlighted in this post). It's one where there is no clear right or wrong answer, just different shades of gray.
I hope this info may you out a bit more.
-Chris