It makes sense in its own twisted way, to be a citizen of the United States you have to be the citizen of a state (or territory), its in the name after all. A lot of citizenie things are based on your state like voting, drivers licence... Since you have to be a citizen of some state, and you need more of a nexus than a borrowed mailing address to call a state your "home" state, the last one you lived in usually claims you. If that state is AK they probably aren't going to pursue you much, if its someplace like CT they may.
Being a citizen and being a tax resident are still two different things, at least when it comes to countries.
Voting is based on citizenship while things like a driver's license isn't tied to citizenship in most countries, you can actually get a driver's license in any country you reside in for that time.