I did the same exact thing and was curious about this as well. 2 years have passed on this question and I couldn’t find any other posts regarding this.
You can collapse the shared stories list so you only see the top most item. After that, it’s a single item that you may choose to use someday. But unless many people voice their concern, I’m not going to add a preference to hide a great source of news discovery.
I would also like to remove my own Blurblog from the sidebar. I don’t use this feature, but since I “shared” a story by accident it’s always there. I already removed the shared story, but it didn’t help.
Just to add to this. The “Shared Stories” counter, on the front/home page, does not go down when a shared story is removed. It would be nice if this number reflected the current shared stories, and not all time shared stories.