Why can't an uploader remove the images they've uploaded?

To be specific, in my instance I uploaded a pair of images that were commissioned for me, only to realize that I’d uploaded the wrong versions (the ones with a very high resolution rather than the images at the source released on the artist’s DA), and thus I submitted a takedown report a couple minutes after.
 
However, it seems only an artist can request a takedown of an image, and frankly, that makes no sense to me. I made a huge mistake, and am not allowed to correct it… so I kind of question the reasoning and wisdom of that policy.

@Dusk Raven  

 
I’ve seen plenty of images removed at uploader’s request, just go ahead and report the image and say that.
 
EDIT: Also, don’t worry about uploading the lower resolution; when someone uploads the high-res it’ll get merged into it. That’s 90% of the duplicates that get merged. You don’t have to do a thing about that.

@WingbeatPony  
I was told outright when I received a reply to the report that “only the original artist may request the takedown of their artwork.”
 
Also, you misunderstand, I uploaded the higher-resolution artwork when I was supposed (presumably) to upload the lower resolution version.

There are a myriad of reasons why this is so, the primary being simply “art owner = artist”. Exceptions are not something that goes well, because for every exception possible there are 14 rules lawyers ready to be as obnoxious as is superhumanly possible.

@Dusk Raven  
I would try reporting the image (regular report) and mentioning that you accidentally uploaded a high-res version of it and needed to replace it with a lower-res version.

@The Smiling Pony  
So why can someone upload art they don’t own yet can’t takedown the images they themselves have uploaded, especially in the case of a mistaken upload?
 
@SuperSupermario24  
That’s basically what I did. Still denied.

@SuperSupermario24
 
@The Smiling Pony  

@The Smiling Pony  
So basically you’re going to keep it until the artist actually says it needs to be taken down?
 
Honestly, I wouldn’t take that approach. I know nothing about the artist, but I’m worried that they might get angry that exclusive versions of their images are getting uploaded on the site and demand a takedown of all their art, or something like that. That might sound a little paranoid, but you know how some people can be.

@Dusk Raven  
Practically all images are uploaded first to DA or Tumblr, where their system very explicitly favours the reupload of those images to other sites; those “Share” buttons and oEmbed features aren’t eastereggs. Takedown is a different matter, as that immediately asserts ownership of the image, which only the artists have unless they’ve signed a formal document transferring some rights.
 
We have no idea of what arrangement you and the artist have, and not the time to investigate every report of this kind individually. For all we know this is an image the artist wants to present to the world and you’re sour with them and want to remove legitimate image they can use to advertise. Or it was an honest mistake. We don’t have the resources for all that, so the rules are simple: art takedown is artist only.
 
This is final.

@SuperSupermario24  
There was no indication on the sources that the high res [Which is available at the source, though that could be artist error] are exclusive. Which is why I had asked for Dusk Raven to contact the artist concerning this.