As opposed to the northern/southern hemisphere that has:
- a clear reference point (equators)
- traditionally we don’t model a rotation north/south
Western/eastern hemisphere
- doesn’t have a clear reference (Greenwich?)
- traditionally we model rotation on the north/south axis so western/eastern would depend from the time


You can say whatever you like and be wrong at the same time. The idea of being a “western nation” and the importance thereof long predates the United States being a great power.