It would be possible to structure codetermination in a legally binding way that employees no matter where in the world have the exact same rights (barring laws

It would be possible to structure codetermination in a legally binding way that employees no matter where in the world have the exact same rights (barring laws in other countries restricting such a thing). As that goes beyond what German law requires most companies would probably not agree to that but it clearly shows how hollow the statements of management in this case are. (It should be noted that the relevant German law considers "Betriebe" and "Betriebsteile" as the unit where employees are represented, so each individual location of a company is usually considered separate and employees at one location have almost no say regarding employees in other locations. In that way, the lawmakers had the same thought process as you)