If you believe this, I am genuinely curious as to what you would consider the “gravest of dangers” to be.
* Asteroid impacts like Chicxulub.
* The Sun eventually inflating into a red giant and eating Earth, though this assumes we're both still around and haven't become spaceborne en masse.
* Pandemics such as The Black Death and, indeed, covid for a recent example.
* Social, political, or commercial intrigue.
* Cancer.
"AI" is a known threat that can be adequately defended against, so I agree with the sentiment that it's stupid to call it a "gravest of dangers".
We would have years to deflect an asteroid, but just minutes to react to a mass ICBM launch.
We have the technology available now to deflect asteroids (ironically, with nukes!), but no country has built up sufficient ballistic missile defence to shield themselves from a first strike.
The Sun expanding (or changing in any impactful way) won't be a problem for hundreds of millions of years. Nuclear war could be triggered today. The US is literally sending about a hundred billion in weapons (total) to kill the soldiers of a nuclear-armed belligerent state... right now!
Pendemics tend to fizzle because pathogens that kill too fast are self-limiting. Merely making people sick is selected for, because that leads to increased disease spread by the infectious -- but alive -- victims.
Societies, politics, and commerce have been more stable than ever in human history, and are become more stable over time, not less.
A cure for cancer in the next two decades is looking increasingly likely. Techniques such as individual rapid gene sequencing, custom mRNA anti-cancer vaccines, CRISPR/Cas9, AlphaFold 3, etc... are building up to a toolkit that will eventually allow us to treat pretty much any human illness, possibly including old age itself.
All bombs are bad, whether they're conventional or nuclear is irrelevant. For that matter, all wars are bad and should be avoided unless no other options remain.
Likewise, "AI" is just as much a threat as any other intelligent being or computer program depending on which line of thought you subscribe to. "AI" is not a "gravest of dangers".