It is true that state corporate law generally requires managers to maximize shareholder value. However, managers are generally also protected by the "business judgment rule" which gives them wide discretion in the pursuit of profits. Essentially, any rational reasoning behind a business decision will be upheld. It is almost certain that managers could legitimately refuse to do business with China on the basis that doing so would create a backlash in the U.S. and decrease profits more than entering the China market would increase profits. There is no conceivable situation in which corporate managers could be held liable for failing to enter the China market.