What is the theme in Startide Rising by David Brin?

Religion fills Startide Rising by David Brin explicitly and implicitly. Explicitly, war over the planet Kithrup is all the more savage because it is a holy war. All of the major powers in the Five Galaxies are determined to own whatever the exploratory vehicle Streaker has found and removed from the mysterious Derelict Fleet. To think, like Lt. Takkata-Jim and Dr. Metz, that the eventual victor will negotiate with and free them after getting whatever data and artifacts it wants is, in Capt. Creideiki's opinion fatally naïve, given the nature of the war. Various scenes among the Galactics makes clear that no mercy will be shown to the vanquished or to the Earthlings when they are captured.