You kind of touched on it, China are very prideful and they didn't build them, that's why they covered them up.

My theory is that the tall, white skinned people with red/blonde hair were the builders. They found mummies fitting this description recently in China. People fitting this description have been found near the pyramids in Egypt, the pyramids in Peru and other locations. My believe is that these people were the survivers of Atlantis. There are ancient documents from Ireland, the Basque region of Spain and a small group of people on the northern tip of Africa that all have Rh- blood. I believe these people are the ones that kick started civilizations around the world. This explains the similar building style of the Pyramids and megaliths which still haven't really been explained.

Back to China. I think they covered the Pyramids because of their pride. They don't want to admit that white people were responsible for these magnificent structures. Again, just my theory.