You are confusing business with friendship. There are many chinese restaurants and chinatowns in USA, does it means USA and China are friends?
Friends are people you regulary visit and spend happy times with. You talk to friends about life, social events, vacation, marriage etc. Friends share intimated details to each others that outsiders dont get to hear.
Business means trading. A Vietnamese pho seller in Germany sells their pho to any Germans, thats all. It is just business transaction with no feelings. Every Germans customers who visits Viet restaurant dont care about anyting but eating Pho.
I would love to read or hear news that every Germans would love to take the bullets for Viets in every aspects. No matter the love you show for Germany, for average german you are just an Ausländer.