Now Tolkie-esque fantasy, you might have a point...But D&D isn't just based on Tolkien-esque fantasy...how about swords & sorcery, where regardless of how they are portrayed there are representations of cultures besides those that are euro-centric?
Yes, like I said D&D seems about equally based on Tolkienesque high fantasy (knights, dragons, elves, dwarves) and swords & sorcery (demons, elementals, cultists, sorcererers, giant carnivorous apes). The art has varied over the years (eg Elmore's art that defined Mentzer D&D was very much in the high fantasy tradition); but I agree there has rarely been the diversity of the characters in eg the two Conan movies, where it clearly wasn't for Political Correctness/Diversity purposes.