1. Insults don't solve anything 2. Uploading own stuff is only looked down to, but not forbidden^^.
Still, if you let one guy do it, Danbooru will become sankaku complex. If you upload stuff like this, be prepared to have it be deleted and your upload limit consequentially reduced, but holy cow. Check out the deleted post section every so often. Sometimes there is a real gem in there that isn't Danbooru quality but still pretty great.
Deleted posts are a disdained, but important part of Danbooru. They are like Jack in the box tacos. Sometimes you just want to eat some shitty food every so often.
Posting one's own art is severely looked down upon, and there are two reasons behind this:
Firstly, artists tend to be biased when it comes to judging the quality of their own work. What looks good to you may be regarded as mediocre to Danbooru moderators.
Secondly, allowing posting of own work (self-posting) will cause a sudden spike of sub-par uploads as users mistake us for another Pixiv or Deviantart, far beyond the scope and capacity of Danbooru.
More suitable sites to upload your own art to include Deviantart and Pixiv.
Admins and moderators are especially harsh on self-posting artists, lashing out penalties without remorse. The one and only way to feature your art on Danbooru is to show immense talent and skill elsewhere, and with that, captivate some fans on the other side of the Internet into uploading your art.
Has the entirety of howto:upload ever actually been official policy? That bit about artists uploading their own work certainly isn't mentioned in the Terms of Service, and the most recent forum discussion on the subject (topic #12128) was utterly inconclusive.
Also, the section you quoted was a revision by user #323224, who I'm pretty sure was never in a position to make rules for this site. The original version was much more moderate in tone and didn't expressly forbid self-uploads:
Uploading One's own Art is looked down upon.
This is because it's generally thought that artists are biased when it comes to judging the quality of their own work. Only in very limited cases are such posts accepted, and posting sub-par creations of your own can result in being penalized. Understand the risks before considering posting your own work. More suitable sites to upload your own art to include Deviantart and Pixiv.
...the most recent forum discussion on the subject (topic #12128) was utterly inconclusive.
Thanks for bringing up that topic. There was no rulings that came out of that discussion, although the general thought was that all self uploads should at least go through the moderation queue even if the poster has "unlimited uploads" permission.
If the post makes it through the moderation queue and is approved by someone with the "approve posts" permission, then at least someone else signed off on it and thought it was worthy to be on Danbooru.
In case someone still disagrees with the quality of the post after it is approved, it can always be flagged and go through the moderation queue again.
And that are exact the words I used. Thank you for supporting me^^. So, it's pretty simple: Looked down = higher quality standards. Look at the first of Tony Guisando's uploads here. They were uploaded by him, but approved, since they've met the higher upload standards.
Has the entirety of howto:upload ever actually been official policy? That bit about artists uploading their own work certainly isn't mentioned in the Terms of Service, and the most recent forum discussion on the subject (topic #12128) was utterly inconclusive.
/me shrugs.
And Danbooru forum discussions are rarely conclusive. Bonus points if the last post in the topic ended with a question mark.
Also, the section you quoted was a revision by user #323224, who I'm pretty sure was never in a position to make rules for this site.
I don't know much about this user, but (s)he has written quite a few seemingly official wiki entries. See also topic #8007, topic #8673, and their feedback.