The table in http://en.wikipedia.org/wiki/International_taxation#Individu... states "no" for "taxes foreign income of nonresident citizens" for China. Is that incorrect?
Even austrailia taxes worldwide income, America is not that unique here.
Taxing foreign income of tax-residents is, as you said, common, most first-world countries do it.
Do Chinese laws provide for taxing Singapore income of Chinese citizens who permanently live and work in Singapore?
If so, is it a matter of not recognizing the citizen is non-resident in China (e.g. claiming it is a "temporary" non-residency)?
Yet other countries don't charge for this much more tangible privilege.
The US passport also isn't even in the top 10 most valuable ones to hold for travel https://www.henleyglobal.com/international-visa-restrictions...
Of course, you're probably right. The real lesson here is to including supporting evidence and not just your feelings.
I'm fairly sure America is the only country that taxes non-resident citizens. Why do you think America is right and every other country is wrong?