This reminds me of the book War before Civilization, about the archeological evidence for pre-historical war and the many attempts to dismiss it, to declare walls merely symbolical (symbols of what?), weapons as means of exchange (valuable why?). A water pipe network is evidence of a centralized authority in the same way that a wall or a weapon is evidence of conflict.
I think the case for "weapons mean war" or even "walls mean war" (weaker, walls can be built for privacy or defense against theft, but larger ones make a good case) is a lot stronger than the case for "infrastructure implies central authority". Some complex projects can and do get done in unstratified social contexts, and /tons/ of them get done with leadership/authority that only exists within the context of the project itself (and doesn't necessitate being in charge of other things or having more social status in unrelated contexts), which could have been the case for this site
Making the claim that the archaeologists are self-evidently wrong here is definitely begging the question. They may well be wrong, but not from logical inevitablity
