I definitely agree that there is an “anti-oriental” bias as to why Europe is considered a continent, but at the same time it does make sense to have a distinction between the continents. Basing continents simply off of tectonics plates gets rough very quick, as Asia itself is divided into several plates (especially in Siberia, Eastern China, and Southeast Asia) and a large part of Siberia is itself located on the North American plate.

Plus there is a very decent natural “land border” in the form of the Urals and Western Steppes, both of which are very very lightly populated where the European border is drawn.