Nell:
Western artist name; western-ish style; copyright that doesn't natively have an anime style.
Most posts tagged with this artist were approved by various Approvers and both have a similar style and are under the same copyright, so I think the issue is probably something else. It would be best to let the Approvers themselves explain why they passed it over. Specific advice from non-Approvers like us could potentially mislead other users. As for artists and nationality, see forum #128234 and forum #163736.
Nell said:
The bright colours also bring to mind those danger-hair SJW type people, which weebs typically loathe, so no doubt that biases the image toward deletion – not that it necessarily should, but it will.
You mean the feather hair ornament? I don't think anyone's going to mistake that for dyed hair. Besides, Danbooru's userbase is pretty politically diverse, and I've seen comments from some Approvers here and there that suggest their political alignments fall somewhere to the left, so I doubt those specific Approvers buy into that stereotype anyway. Not to mention the obvious fact that anime has no shortage of characters with unusual hair colors.