Which, of course, is irrelevant for US citizens living in the UK, which is what this article discusses because the UK is a higher-tax country than the US. US citizens are eligible to claim a foreign tax credit against their domestic tax liabilities, which avoids the issue of double taxation.
Worldwide taxation prevents US citizens from mooching off the benefits of US citizenship while evading taxation as tax exiles. However, I'm reasonably sure that no US resident of the UK is there as a tax exile.
What would be those benefits of US citizenship exactly? I understand how maybe a half century or more ago being a US citizen conferred great benefits compared to citizenship of other less enlightened nations. Today, not so much.
Citizenship of dozens of European nations, Japan, Australia, Canada, New Zealand etc provide all the benefits and freedoms that the US provides without the hassle from over-intrusive tax authorities and other state-run organizations.
The old idea that if you get into trouble overseas the great, overwhelming might of the US government will swoop down in all its majesty to rescue you from the clutches of the devious foreigners is I’m afraid a complete myth. The US government will do diddly squat for you other than check if you’ve paid your taxes.