It also means the US has more interest in that person than if they were a citizen of another nation, not residing here.
See if you wrap your brain around this. Say you were a refugee from the former Soviet Union with a green card in the U.S. Say also you were a dissident journalist who then got a job with WaPo. Say then an up and coming young KGB officer, let’s call him Vlad from Leningrad came and assasinated you while you were on holiday in the UK on orders of Andropov. Are you seriously telling me that our government wouldn’t have more of an interest in your fate than a Soviet citizen killed domestically in Russia? Are you also telling me that Vlad and crew would have had the right to do that because technically you were still a Soviet citizen?
In other words, stop being an ass.