I feel obligated to point out, though, that I have always been a sucker for ideas I find aesthetically pleasing. The cosmic sweep of the thing - an interstellar kula chain - affirming the differences and at the same time emphasizing the similarities of all the intelligent races in the galaxy - tying them together, building common traditions... The notion strikes me as kind of fine.
I would remind you to notice where the claim of consensus is invoked. Consensus is invoked only in situations where the science is not solid enough. Nobody says the consensus of scientists agrees that E=mc2. Nobody says the consensus is that the sun is 93 million miles away. It would never occur to anyone to speak that way.