I'm of the belief that the ability to keep your work, voluntary exchanges, and assets private contribute to a free society in the same way that attorney/client privilege, priest/community, and spousal privilege all exist.
Now, in the United States, we don't have that and people know that and live with that. But people doing business in Switzerland are under the impression that they have a very private, safe relationship with their banker, the same way you'd have with your lawyer, psychiatrist, priest, or spouse. This man breaching that is doing a very serious thing.
This goes beyond politics. When you have a private relationship with a professional, sanctioned by the local law, that says that you have private confidence and that's betrayed... that's serious. If you don't believe in the Swiss banking system, not working there is acceptable. Protesting it is acceptable. Taking on a fiduciary duty of loyalty and confidence, and then breaching it... that's serious.
The average American might not think this way, because they don't have a private relationship with their banker. But generalize this to all duty - this man pledged duty, people were under the impression that he had a duty of confidence to them, and he breached that. This doesn't get into right/wrong, but it's something worth thinking about.