Why would an AI be civilization ending? maybe it will be civilization-enhancing. Any line of reasoning that leads you to "AI will be bad for humanity" could just as easily be "AI will be good for humanity."
As the saying goes, extraordinary claims require extraordinary evidence.
That's completely fair but we need to be prepared for both outcomes. And too many commenters in here are just going "Bah! It can't be conscious!" Which to me is a absolutely terrifying way to look at this technology. We don't know that it can't become conscious, and we don't know what would happen if it did.
As the saying goes, extraordinary claims require extraordinary evidence.