Of this place it is specifically said that no sacrifices were made. The "four holy liquids" - water, wine, milk and olive oil - were poured on the altar. Their gifts to the gods were fruits. "Very rare, sacrificial animals." But that doesn't sound at all plausible to me. "The Four Holy Liquids" - come on. Where is the blood, the most sacred liquid? That's why I think the whole story is fabricated and implausible to begin with.
Why did they make sacrifices - I thought you rather had an answer to such questions. Perhaps then, at that time, people communicated more easily with their gods and they, their gods, gave them instructions on what to do. Aren't similar things written in the Bible too?