I wooden rush to judgment on the meaning of all this as it could be more than a feasting site, etc. Perhaps a meeting place for a government, as just one possible explanation. Just think if they had Obamacare back then they might still be around to fill in the gaps.
I think they more likely sacrificed the young and healthy. Perhaps the elderly were left to fend for themselves.
Or it could have been the party site for me and my buddies in the summer after H.S. graduation...........wonder if they found any beer bottle caps?
If only they had a branch manager who had kept a log we might better understand the root meaning of this circle. As it is, it leaves much speculation for those of us who pine for an answer....