The point is Western Civilization vastly borrowed from those civilizations and areas. The very religion most people practice in Europe is a Near Eastern religion (Christianity is an offshoot of Judaism), our alphabet is Phoenician traced back(Phoenician->Greek->Latin), our number system is Arabic.
What about indigenous Americans? Mesoamericans and South Americans such as Mayans, Aztecs, Incas, etc. were far-western geographically and in Latin America those people still exist and the general culture is a blend of European, Indigenous, African and to a smaller extent Near Eastern. Why is Latin America not counted as western? Latin America shares a religion with much of Europe (Catholicism) and the main language of trade is a European one.
Ultimately - "western" is usually a weasel word for "white".