Visa releases iPhone app with discounts, merchant directory

Visa is a business, they made their decision based on the impact it would have for their business (right or wrong... this could turn out to hurt their bottom line). Numerous factors exist - concern about backlash by people who disagree with the leak philosophy, the opposite concern, free press, bad press, worry about legal implications, etc. There's nothing here even remotely similar to Nazi Germany, and all you accomplish by claiming as much is trivializing the tragedies that occurred there.

If you don't like a business and don't want to patronize them that's fine, do whatever you want. But while you're feeling all noble, keep in mind that every business you encounter is doing its best to make money - if you start avoiding all establishments which are profit-minded you'll find yourself cold and hungry in a secluded wilderness.