>I feel like our primary disagreement would not be on the facts but on whether it's justified to use the phrase Doomsday cultists for people who are flailing in response to a genuine threat. Is that fair?

Cultism is a social phenomenon with common patterns, and I think the shoe fits here, independent of the belief system. Once I lived with a follower of Adi Da, who believed the world must awaken to a new level of consciousness, which he generally described in terms of collective stewardship of the environment. I agreed with that, but I would call him a cult member, not because he took that belief to an extreme or didn't base it on sound science, but because he was a manipulable psychological type (a serial joiner of new movements in the 1960s) recruited by a prophet in order to proselytize a vision of the world in which a select few have the level of devotion required to play a decisive role in the fate of humanity. Similarly, I think the AGI people take advantage of anxiety-disordered young men, like I used to be.