If you're trying to imply that the US isn't completely crazy town about tax, you seem to have missed the enforced citizen tax returns for salaried employees and the fact that citizenship makes you liable for US tax regardless of residence and income origin.
> the fact that citizenship makes you liable for US tax regardless of residence and income origin
Without which, evasion becomes trivial for the wealthy.
You can offset taxes paid in foreign jurisdictions through a deduction or credit. You just can't set up a mailing address in a no tax jurisdiction to launder your earnings.
I'm just saying the answer is not "basically yes" as the comment I replied to said. Unless you are a US citizen (even if you don't live in the US), where yes, the answer is always "yes, you have to pay".