I'm guessing there's more of THAT than Joe Williams of Milwauki moving to Poland and relinquishing US citizenship.
It's very unlikely that any in this number fall into that camp. The terrorists don't want to draw attention to themselves and want to re-enter the USA.
The people surrendering their passports are high earning entrepreneurs. The problem they have is two fold. They pay taxes on their earnings in the country they are in and pay taxes on their earnings in the USA. I'm not sure if it applys to personal returns, but if they file as a corporation they can get a $90,000 tax exemption but then they will pay corp. tax rates in both countries. The second problem they have is most banks are not to eager to take American customers because of the reporting requirements and consequences they face if the customer doesn't accurately report their income.
So if your overseas and see that the USA is becoming a banana republic why continue paying taxes twice.