Upload and Share tend to be the same thing for most users. You want this on that. I don't think it's coincidence that the share icon looks like an upload icon in iOS7.
This really isn't about sharing, its about sending the content outwards. The subsequent action will dictate whether its to share or pass to another program or even copying for a later paste.
Its sending the "thing" outwards...away from yourself. To something else.
The same thing happen with information, it goes from one place to another. The fact that this action takes many forms doesn't really matter.