You could say an obligation comes from the USA providing a legal framework and a market and the military force needed to dissuade others (countries, pirates, terrorists, etc.) from interfering too much.

No obligation is required however. The USA can just insist. This is what China does, notably, and China is not alone. Countries all around the world are forcing corporations to serve their people. That is kind of the point of a country, using the threat of force (prison, asset seizure, war, etc.) to serve a group of people.