2 letter TLDs/country-code TLDs, are determined by ISO 3166-1 alpha-2 country codes, and having a country code doesn't necessarily mean a country or a state.
There are a bunch on there that I wouldn't consider states, e.g. both UN/EU are exceptionally reserved and have `.un` and `.eu`. Antarctica also has `.aq`.
The Heard Island and McDonald Islands has `.hm`, and it's not a state (since it has no population) but I guess it is controlled by Australia.