In your second example, if a Swiss banker conducted a transaction with a U.S. bank and did not adhere to U.S. banking law, then they did violate U.S. law and can be tried in absentia. They are not being tried for something that is legal in their own country, they are being tried for not following U.S. law.
If Switzerland does not wish to extradite, then the penalty is that the individual can never set foot on U.S. soil under threat of arrest.
The U.S. Justice Department is not "transporting beyond the seas" the individual, and the individual did not 'do something that is legal in his home country.'
“In your second example, if a Swiss banker conducted a transaction with a U.S. bank and did not adhere to U.S. banking law, then they did violate U.S. law and can be tried in absentia. They are not being tried for something that is legal in their own country, they are being tried for not following U.S. law.”
Then what happens someday when you’re on a trip to Germany (for instance) and when you land at the airport you get arrested and sent to the UK to face trial for writing things on Free Republic that violate UK hate speech laws?
Will you stand on principle and passively accept your punishment?