Lola,
What you say is not quite true. Switzerland is part of the Schengen area, which is a common passport area. Once you are in the Schengen area you can travel to any other Schengen area country without restriction. Any limits on being in the Schengen area (90 day in 180 limit, requirement to have a visa) apply to the Schengen area as a whole, including Switzerland.
The current row is because the USA still requires visas from citizens of some Schengen countries (for example Bulgarians) and refuses to drop this requirement. the Schengen treaty is "one for all and all for one", if a country imposes visas on any Schengen member, Schengen has to impose visas on citizens of that country. This row will run and run, but neither side really wants to impose a full visa requirement, as then the other side will and that will be a major bureaucratic requirement. It is a bit like the cold war, nobody wants to shoot first.
But, currently and for the foreseeable future, US citizens do not need a visa for Schengen countries if they are staying as a tourist for less than 90 days in 180.