What, exactly, is the attitude toward duplicates?

I'm not in the business of uploading duplicates myself, but I've had this question bouncing around in my head for a few days.

According to the Upload Rules page, duplicates are prone to being deleted, users are discouraged from uploading them, and approvers are discouraged from approving them.

However, according to the Flags page, you shouldn't flag duplicates for deletion, and you should just make them a parent/child of the thing they're a duplicate of.

So... Duplicates shouldn't be put up, and they also shouldn't be taken down? This interpretation is consistent with what's in the guidelines for duplicates on their own Wiki page, so I'm not saying that I think I'm misunderstanding:

Do not flag a duplicate post for deletion if your only reason is that the post is a duplicate. Parent them to the superior image instead.
[...]
Avoid uploading visually identical posts. If such a post is uploaded, take proper care to tag and parent it correctly.

I'm saying that I still can't wrap my head around the reasoning. How is this not inherently contradictory? What stance on when & where duplicates belong was this born from?

My best guess is that it's specifically discouraged so that people don't try and farm upload slots by uploading duplicates of already-approved images for easy approval. Approvers don't have an upload slot limit, so if they upload a duplicate it's whatever, I guess? If it's a duplicate and of significantly worse quality, then it should be flagged for quality.

If an image is of superior quality, then it's inherently not a duplicate and should be uploaded.

That's just my theory, though. IDK.

Ylimegirl said in forum #423025:

My best guess is that it's specifically discouraged so that people don't try and farm upload slots by uploading duplicates of already-approved images for easy approval. Approvers don't have an upload slot limit, so if they upload a duplicate it's whatever, I guess? If it's a duplicate and of significantly worse quality, then it should be flagged for quality.

If an image is of superior quality, then it's inherently not a duplicate and should be uploaded.

That's just my theory, though. IDK.

That's also how I think of it. I've accidentally uploaded multiple duplicates myself because artists sometimes post cropped images, especially on X/Twitter. Those aren't flagged by NTISAS or Danbooru, and if I don't spot a full image on the artist's page, they get posted.

it needs to be parented so you can actually find the post. this is the same thing we do with revisions and 2 posts from different sources that have different resolution/size

btw while you can't flag duplicates you can flag image samples if the full resolution has been posted.

Thanks, all. I really do appreciate the info.