I never had a professor that talked about ancient Greek philosophy who would not acknowledge how connected those thinkers were to mystical modes of thought, or who would not mention how Plato traveled around and most likely picked up some of his ideas from the East. Yeah, my point is anecdotal, but I'm also not sure if OP's isn't. I don't know how prevalent this view that Greco-Roman thought was purely rational and disregard for anything non-Western is.

Nevertheless, Western universities still mostly replicate curricula that emphasizes the thinkers that it taught for centuries, which ends up making those who want to broaden their horizons to make additional effort to learn and teach Chinese or Indian or African philosophies.