"There's a danger we'll be able to fly to Jupiter and bring home a Jupiterian life-form that will destroy humanity. Therefore we should stop all space exploration."
The doomers take the equation with some wildly improbable step that we can't currently explain or justify, multiply the outcome of that step by "infinitely bad", and conclude that the whole thing must be dangerous. But to amp up the rhetoric, they always skip over the "wildly improbable" part.
Personally, I think this line of argument is driven by the hype cycle more than reality. Use chatGPT or midjourney or whatever for a while, and it's pretty easy to see that we're dramatically overweighting theories of AGI risk, and dramatically underweighting stuff like "disemploying the bottom 80% of the intelligence bell curve" with technologies that automate away lots of formerly white-collar labor.
If I had to put my money on an "existential risk" attributable to AI, it would be economic strife.