The page doesn't load for me and I can't access it directly via ArcGIS Online (arcgis.com/home/item.html?id=ac794499522948da9084dba903513661). May I ask how you removed it from the site? Did you change the sharing or delete the item entirely?
It says it’s shared with the team, that is why you can’t see it. If that is case, it’s not that big of a deal, but it still would be nice to have an easier way to remove it.
This just frustrated me as well. Patrick, some suggested changes:
1) Add something to the "Content Library" page in Hub (edit mode) that at least hints at how to remove content. I'd like to see a link added to each item that says "Remove from Hub" or "Remove from this site". When a user clicks that link, it can show a pop up with text to the effect of "To remove a data item from this content, you must launch ArcGIS Online and unshare the content with the group associated with this Hub site." Then provide a link to the AGO page where we can change the sharing.
2) You suggested that people refer to this help page: Add content to a site—ArcGIS Hub | Documentation . But I don't see where it explains how to "remove" a shared item. Also, the title of that page is "Add content to a site". It really made me think that I wasn't going to find anything on that page about removing (or even changing) content. Maybe change it to "Managing content on a site". But if you're going to do that, please make sure it explains how to remove the content.