...if the Chinese government wants records for an American citizen's account at Bank of America, then America will have no reason to protest since BofA has offices in China, and the principle of extra-territorial subpoenas has been established. If Microsoft loses this case, it will be a terrible precedent, and a victory for oppressive governments all around the world.
So don't do business with banks that have offices in other countries. Move your business to your local credit union. Demonstrating that big banks can be legally required to divulge your data to governments in any country where they operate sounds like a way to break banks' power a bit, and thus a win for humanity.