The complaint is not about having to pay taxes to reflect your status, it's about having to pay accountants etc. to complete forms that show you don't owe any tax to the US.
The United States doesn't actually do much for its citizens; it's the states that do things for citizens, and if you're not in a good state, you get no real value from the United States or any part of your country. It wasn't always this way, but it's been this way for as long as I've been alive.
Sentiment is overrated and irrational if the country's never given you anything, and the United States just doesn't give anything to a substantial volume of its citizens.
A common argument is that the United States gives the right to free speech, or to guns, or to varying abstract concepts, but it would also give this even if everyone stopped paying their taxes and the United States was unable to enforce anything.
I'm a big fan of taxation, and of most laws. The US, though, really doesn't do anything with it that has ever benefit me.
The poster really does seem like, if anything, she cares too much for the country.
Or probably skeptic, because they're planning on moving to a good state.
Or most probably, they don't care. They're moving countries, they probably don't have the most nationalistic bent to them.
I don't hate the United States, I'm just not being unrealistic about how beneficial it's been for me.
Maybe that's what happens when someone means so little to their country?
Regarding the taxation when living abroad, doesn't it actually make sense? Sure it sounds like an oddity because the US are the only to do it, but most emigrants I know still use the consular services of their country of origin every now and then, benefit from its diplomatic protection, and can return any time if circumstances require it (implying they should be contributing to keeping the country safe and functional in the meantime, call it an insurance policy if you will), and probably many other benefits I'm not thinking of. Some countries will even send special forces abroad to recover citizens in danger.
So yeah apparently the practicalities of it suck sometimes (and that should definitively be improved) but in principle it's not as outlandish as it sounds, imo.