Wino,
That's an interesting statement.
A quick look at the IRS site here:
http://www.irs.gov/publications/p54/ar01.html
shows that the basic principle is:
"As a U.S. citizen or resident alien, your worldwide income generally is subject to U.S. income tax, regardless of where you are living. Also, you are subject to the same income tax filing requirements that apply to U.S. citizens or residents living in the United States."
There are many thousands of US expats in Hong Kong (just an example because that's where I live and I know some of them) who would love to know how to avoid paying US tax. As I understand it, you can claim some credit for tax paid overseas, but there is a limit on how much income can be treated in this way (US$80K?) and in any case you can only credit the actual amount of tax paid, so if you are in a low tax environment like HK then you will still have to pay a substantial amount of tax in the US.
A further symptom of this type of behaviour is that banks in HK refuse many types of investments to US Citizens here because were they to offer them the US Government requires the HK bank to send them details of the investment, refusing them a licence to undertake banking in the US if they do not. This is an outrageous, but typical, example of US arrogance.