[geofft]

US citizens gain benefits from the US government by definition, and they have the ability to give up their citizenship if they don't want that. The reason they're taxed is that they are actually subjecting themselves to US jurisdiction, in addition to the jurisdiction of whatever country they're physically in. (For instance, they can choose to leave the country they're currently in and be allowed visa-free entry to any country that permits visa-free entry to US citizens, and of course they can choose to return to the US.)

The Double Irish involves a company in non-Ireland country A doing business with a customer in non-Ireland country B, and routing that transaction through Ireland. I have no issue with either A or B deciding that they ought to tax this transaction, because both countries are relevant.