It isn’t even anglocentric. I’m pretty sure the set of translations from admin_level=* to English on the website doesn’t fully correspond to any country in any dialect of English.
I’ve proposed to replace these translations with more generic bands that would hopefully avoid giving the impression of a specific designation:
It’s part of my larger proposal to fix the situation where the website has two British Englishes and zero American Englishes, causing confusion and warping OSM tagging. Unfortunately, there’s some strong opposition to changing the site’s vocabulary, apart from trivial spelling fixes. But maybe we can get some traction behind these more generic terms too.
Labeling boundaries based on admin_level=* is inherently difficult, because this key basically only indicates how deeply nested the boundary is in a hierarchy. In geocoding, this information is essential for arranging the containing boundaries’ names, but it isn’t really relevant enough to display to the user as a “type” of boundary. Ideally, the site would use a second key such as designation=* or border_type=* to determine the jurisdiction’s formal designation in real-world terms instead of OSM terms.