Follow up question. Why is putting every Asian culture in a blender and taking elements for your setting wrong. Have we not done the same to European cultures with most D&D settings?
I guess I would have to say, because European culture in the time period we use as a basis for Fantasy Settings is far more homogeneous?
Most of our fantasy settings are based on High Medieval to Early Renaissance. Time periods where most of Europe was unified into one or two empires. The Carolingian empire, The Byzantine and Frankish Empires, the Holy Roman Empire. Nearly everyone shared a religion, They were all Christian, through much of it All Catholic (excepting OF COARSE the Jewish and Muslim minorities). While different areas obviously had their own customs and languages, at the same time they were bound by the same laws, had the same religious doctrines, and generally had to learn at least a little of a common language for trade and legal reasons. The term Lingua Franca comes from this time for a reason. It's why fantasy settings HAVE "Common" as a language.
Even after the empires collapsed and smaller monarchies emerged again, ALL THE NOBLE FAMILIES OF EUROPE WERE BLOOD RELATIVES. The Rulers of all the countries started out as first or second cousins, and since nobility was supposed to marry nobility, the sons and daughters of kings married the sons and daughters of kings from other nations, keeping all the royal families linked. Yea, up unto the modern day. Kaiser Wilhelm was the Nephew of Edward VII (King of England leading up to WWI) and First Cousin of George V (King During the war through the late 30's)
So, while Western Europe, yes, does have some cultural differences, they are on the same scale that Brooklyn, Texas, and San Francisco have Cultural differences.
Also, it's worth noting, The process of Blending and Cherry Picking bits and pieces of all White Western European Christian Cultures to make High Fantasy settings, was done BY White Western European Christians (or people of such descent). E.G. JRR Tolkien, CS Lewis, et al.