Conversation so far:
Why was the Maya civilization being investigated?
The agents of the Catholic Church wrote detailed accounts of the Maya, in support of their efforts at evangelization, and absorption of the Maya into the Spanish Empire.
Was there anything bad that caused the investigation as well as the Catholic Church writing detailed accounts in support of their efforts at evangelization?
This was followed by various Spanish priests and colonial officials who left descriptions of ruins they visited in Yucatán and Central America
How did people perceive the Maya civilization to be?
In the 1960s, the distinguished Mayanist J. Eric S. Thompson promoted the ideas that Maya cities were essentially vacant ceremonial centres serving a dispersed population in the forest.

Question: Why did he say this?
Self-contained rewrite: Why did he say this?