A lot of it is subjective, but the bottom line is that if you have a very good quality, HD wallpaper where the only issue is that part of the background has artifacts when you zoom in (and in a lot of cases, it won't even be visible in use on all except really expensive screens - meanwhile, looking at the fact 720p wallpapers are accepted, I assume it's not the site's main target group), it is quite ridiculous and misses the point, sorry.
I myself use a 10 year old laptop with a 1280x800 screen and STILL can see those artefacts on background. Have I miss the point somewhere? I have to repeat myself: I spot a compression artefactss (little squares, distortions, noise, whatever you call it) in ANY part of a wallpaper ➜ low quality ➜ deletion. I just can't allow them to stay here because of reasons I mentioned before. We would have here a tons of low quality walls and that's what we don't want to.
I had a bunch of wallpapers removed exactly like that - excellent quality, excellent lighting, all details of the model and the scenery were very crisp with zero artifacts, but a part of the image was agray wall which had slight artifacts if you looked really closely. Which, by the way, is sometimes inevitable with digital photography.
Yes, I've deleted those 4 walls of course because 'slihgt artefacts' (no, they were clearly visible little squares) were on one third of a wallpaper which is not a small part of it! (even absolutely not interesting, though). Yes, you are right that in some cases it's inevitable to have more noise or grain on wallpapers but in my experience in 95% acceptable walls with these distortions are night shots (higher ISO), vintage or old photos made by film cameras (naturally higher noise) or underwater photos. I am less strict with judging on these kinds of wallpapers. All others should and have to be high quality on all parts otherways the will gone.
I totally get the point about "uninteresting", but my point is:
1) A lot of the stuff that makes it to the "best of the worst" thread stays. I'll leave it to you to judge if those are mostly better than a high-quality wallpaper with a background of worse quality.
Absolutly not valid argument: from tens of thousands of users just a very few (hardcore almost everyday-visiting users) are posting on this thread. It's not bad at all - they say their opinion in that form; but it's deffinetely not a majority and can't be taken as a decisive. Btw, content of a wallpaper has nothing to do with its quality.
2) I see plenty of wallpapers that have no artifacts but the overall photo quality is below what I'd consider good and clear. If I were to report all of those, trust me you would get spammed.
Well, just no :)