He acknowledged he had underestimated the US authorities and the risk of penalties.
While stressing the bank had always respected Swiss law, he admitted exploiting "differences between the (legal systems) in Switzerland and the United States."Basically, as with many criminals, what he really regrets is (i) having been discovered and (ii) being too exposed on what the United States could do. As his minions hawked Wegelin to U.S. taxpayers fleeing or driven from UBS, he was assuring them that there was nothing the U.S. could do to Wegelin's ability to keep the client data secret. He was wrong.
The article also alludes to the situation of the Holocaust Jews with money in Swiss banks. Hummler uses that episode to paint Swiss bank secrecy as a good thing. That episode had its darker side, of course, when the Swiss banks just decided not to return the money in many cases. See The Wikipedia entry, World Jewish Congress lawsuit against Swiss banks (Wikipedia), here. This is a mixed defense of secrecy as implemented by the Swiss.