It's straight up absurd. AI is going to have no appreciable effect on this, because it would simply be disseminating existing knowledge. You can already look up how to build a nuclear bomb. It's not some kind of big secret that nobody's allowed to know. The same goes for all the other world-ending scenarios. AI can't act on its own in the physical world. Even when it eventually does, it will be bound by the same limitations people are.
I agree that the real dangers AI presents are much more mundane. People being able to do things so much more efficiently is going to cause instability in people's lives whose jobs it will affect. It won't replace everyone, but it will cause problems - people have to learn new skills, find new jobs etc.