This is not a Swiss specific thing. The US is one of the few countries that taxes citizens (and permanent residents) while the they don't live in the US. Consequently citizens have to self report their foreign income and foreign taxes. There are various tax treaties, but the US person will essentially have to pay the difference between the foreign taxes and the US taxes on that money (that at no point went anywhere near the US, nor any services it provides).
But of course that wasn't enough. The FATCA law requires foreign institutions to also report back to the US. https://en.wikipedia.org/wiki/Foreign_Account_Tax_Compliance...
> The Foreign Account Tax Compliance Act (FATCA) is a United States federal law requiring United States persons (including those living outside the U.S.) to have yearly reported themselves and their non-U.S.financial accounts to the Financial Crimes Enforcement Network (FINCEN), and requires all non-US (Foreign) Financial Institutions (FFI's) to search their records for suspected US persons for reporting their assets and identities to the US Treasury.
Note the last part. The burden imposed by FATCA on those institutions is so high, that they are refusing to have any US related people as customers. Heck the FATCA law is so wide reaching and onerous that a friend in Sri Lanka was bitching about having to implement it at their company, even though they don't employ a single US related person.
The net result is US citizens living abroad are giving up citizenship rather than deal with all this crap. It is noticeable how under represented Americans expats are, and there will be increasingly fewer. (As a counter-example, you will find Brits everywhere.) This will harm the country and its integration into the rest of the world (economically, politically etc).
http://www.bbc.com/news/magazine-24135021
http://www.heritage.org/research/reports/2014/06/fatca-hurts...
http://fatca.hsbc.com/