That's a serious case of Google-Image-Searchitis. My theory: somebody googled for "settings icon", swore to himself to get proper artwork later, forgot, and there we have it. (Yes, I'm guilty of that too, but I usually don't forget)
Which is why we need a consistent way to embed license data into media. Not as "enforceable" DRM but as metadata that is preserved by image editing software and can be checked automatically when you are about to send your creation to production. EXIF theoretically allows for this but it is hardly ever used.
Sounds like this is a people problem, not a technical problem.