WHY is this SO HARD???????
When I click on Duplicate 1 Photo why does it not duplicate the photo????
Why do I have to be in a special view?
Each of the predefined views is showing only a subset of your photos, specific for this view. This is what the different views have been designed for. For example, the "Imports" view is showing only photos that have been imported to Photos, not photos saved to Photos in other ways, for example by duplication. You cannot duplicate photos in "Imports" because the duplicated photo could not be added to "Imports" as it will be not be an imported photo; the same reason why we cannot import photos directly into "Recently Deleted" or duplicate photos in "Recently Deleted".
We can duplicate photos in any predefined album where the duplicate will fit into the predefined album according to the rules for the album - All Photos, Recents, all media type albums, because duplication does not change the type of the media. But duplication will change the "date added", so you may not find the duplicate easily in the view you are currently in, if the view is sorted by the "Date added" and not the date the photo has been taken.