Another possibility is that this was another group of hominids, not homo sapiens, and that that did in fact die out.

But honestly I'm not qualified to say much more in the subject than I have, I think it's a fascinating hypothesis & that the evidence that the bones were broken apart by being impacted with stones, in a similar manner to how bones are broken up to extract marrow, is compelling. And that the further isotopic evidence suggesting it was the stones found around the site, rather than construction equipment, is also compelling. But I'm not an archaeologist, and when the debate settles, I'll accept the conclusion they come to.

[1] Not to be pedantic, just to note because I find it fascinating, but the current ice age hasn't ended, this was the "last glacial period". Between ice ages there can be things like palm trees and turtles living at the poles. We're currently in an interglacial period of an ongoing ice age.