I think I know why Arn did this, but as it stands now, as soon as a category becomes a subcategory of any other category, it's removed from the main page. I think that can be a little confusing, because then unnecessary categories get created as people don't realize a category exists.
So maybe it's best to settle for short-term confusion and have all categories appear on the main page. Or perhaps someone else has a better idea.
So maybe it's best to settle for short-term confusion and have all categories appear on the main page. Or perhaps someone else has a better idea.