From the link:
"The very high temperature melt-glass appears identical to that produced in known cosmic impact events such as Meteor Crater in Arizona, and the Australasian tektite field," said Kennett.
"The melt material also matches melt-glass produced by the Trinity nuclear airburst of 1945 in Socorro, New Mexico," he continued. "The extreme temperatures required are equal to those of an atomic bomb blast, high enough to make sand melt and boil."
I can think of another force that can produce those temps.
Interesting that they noted that the same sort of melt-glass resulted from a non-impact senario, but didn't follow that line of thought any further.
Also from the link: "The presence of a thick charcoal layer in the ancient village in Syria indicates a major fire associated with the melt-glass and impact spherules 12,900 years ago," he continued. "Evidence suggests that the effects on that settlement and its inhabitants would have been severe."
There is one major problem with the impact hypothesis: Where's the crater (or craters)? AFAIK the present explanation is that the object hit a glacier, and thus left no crater at all. But if it hit a huge slab of ice, then how did it get hot enough to melt sand beneath the glacier and how did the remnants get scattered all over the place, from California to (at least) Syria ? Why is there a "thick charcoal layer" in Syria but not other places?
One way that can account for all the available evidence is a massive electrical arc (think of a huge welding rod striking a metallic plate) moving across the affected area.
I'd previously thought that this might
have been caused by a passing celestial object that affected the area from about South 10 to 15 degrees latitude to about 45 degrees North latitude. Now I think that it couldn't have spread further South than the Equator because the curvature of the Earth would have shielded most of the discharge. This, of course, is speculation but it's a better explanation than an impact without a crater.