unfortunately the terminology here is very unclear, but i think you're right; the megafauna dying in america was the https://en.wikipedia.org/wiki/Late_Pleistocene_extinctions and happened before the https://en.wikipedia.org/wiki/Younger_Dryas, which is the '1200-year ice age' whose name the nyt didn't think was important enough to mention

https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesi... discusses the comet impact hypothesis, which it describes as 'controversial and not widely accepted by relevant experts'

also note from https://en.wikipedia.org/wiki/Younger_Dryas that the younger dryas didn't happen in south america, which is where the largest extinction of american megafauna happened; instead south america had the milder and earlier https://en.wikipedia.org/wiki/Antarctic_Cold_Reversal

however, it seems obvious that a widespread glaciation would have caused some extinctions, and there was a long tail of megafauna extinctions that extended long after the younger dryas. glyptodonts like https://en.wikipedia.org/wiki/Doedicurus apparently didn't become extinct until only 8000 years ago, and the wrangel island mammoths didn't become extinct until only 4000 years ago

Could both statements not be true?

The ice age may have encouraged humans to hunt more mammals than previously required.

You're correct, the comet theory has been debunked for years at this point.

>I thought the Americas' megafauna died after the ice age, not because of it?

There was a article that had "proof" that megafauna extinction was a result of Humans moving into that area. I think I saw it here in NH.

To me that is the theory I agree with.

I think it's a theory that should be regarded with suspicion. It too neatly aligns with modern world views and environmental concerns. That's not to say it's false, it may turn out to be true. Just as should tread carefully with it recognizing the social bias supporting it

There's probably social bias against it too, to the extent that it already means Australians burned down and killed everything, this would just be transferring that to other places.

This is after the "ice age", meaning after the glacial period. The Younger Dryas was a period during the current inter-glacial where temperatures went down a great deal for a while -- a mini ice age within an inter-glacial period.