What interest does it serve to make their life hard? She just wants to pay taxes where she works and lives. And what’s wrong with being a “rootless cosmopolitan

What interest does it serve to make their life hard? She just wants to pay taxes where she works and lives. And what’s wrong with being a “rootless cosmopolitan”? I don’t think anyone would mind losing their US citizenship as soon as they leave the country, if you could also regain it as soon as you enter