Note that this claim is distinct from the claim that (due to general economic theory) it's more beneficial for the AIs to trade with us than to destroy us. We already have enough citations for that argument, what we're looking for are arguments saying that destroying humans would mean losing something essentially irreplaceable.

I don't think there are particularly good arguments in this department (those two quoted one are certainly not correct). Except the trade argument it might happen that it would be uneconomic for AGI to harvest atoms from our bodies.

As for "essentially irreplaceable" - in a very particular sense the exact arrangement of particles each second of every human being is "unique" and "essentially irreplaceable" (bar now quantum mechanics). An extreme "archivist/rare art collector/Jain monk" AI might want to keep therefore these collections (or some of their snapshots), but I don't see this to be too compelling. I am sure we could win a lot of sympathy if AGI could be shown to automatically entail some sort of ultimate compassion, but I think it is more likely we have to make it so (hence the FAI effort).

If I want to be around to see the last moments of Sun, I will feel a sting of guilt that the Universe is slightly less efficient because it is running me, rather than using those resources for some better, deeper experiencing, more seeing observer.