Since you seem to be arguing against my point why don't you go back and read the post you referenced THE GREAT IMPACT DEBATE or more directly THE Great Impact Debate I: Benefits of Hard Bodies

Alan Harris: First of all, in contradiction to Benny Peiser's remarks, Peter
Ward has presented data showing that while it is true that the majority of
species that have ever existed are now extinct, only a minority of those, a
few percent in fact, were victims of mass extinctions. Instead, most extinct
species have come to an end at some random time between mass extinctions.
The point is, extinctions happen all the time. A mass extinction may produce
a very high spike in the momentary rate of extinctions, but averaged over a
very long time constitute only a minor fraction of the total extinctions.

The second contradictory point Ward has made, this time to one of Chapman's
comments, is that the evidence that the Permian extinction is due to an
impact is close to nil. To be sure, this is still an unsettled question, and
by no means has anyone offered a definitive alternative to impacts, but the
evidence supporting an impact cause is very weak.

I attended a meeting in which Walter Alvarez, one of the originators of the
K/T impact scenario, gave essentially the same evaluation of the evidence
(or lack thereof) regarding the Permian extinction. He reflected on his
battle to gain acceptance on the impact cause of the K/T extinction, and was
almost apologetic in observing that everyone now assumes other extinctions
must be caused by impacts. In fact, the evidence is really persuasive for
only one extinction - the K/T one that ended the reign of the dinosaurs.
Combining these two points - that most species meet extinction not as a part
of a mass extinction, and that only one out of four major (and none of many
minor) extinctions can be definitely attributed to an impact - it appears
that death by asteroid is not the most likely end in store for our species.
We should not be obsessed with it to the exclusion of other environmental
and societal concerns.

Peter Ward: The 1980 discovery that a mass extinction had been caused by an
asteroid impact was revolutionary. Questions then arose regarding the
frequency of asteroid and comet impacts on Earth. By examining the size and
frequency of meteor impact craters, Gene Shoemaker and others calculated
that we might expect a K/T-sized impact every 100 million years. This
frequency roughly fits the facts on Earth: there have been five major
extinctions in the past 500 million years. But the K/T extinction is the
only one undoubtedly caused by an impact. And a salient fact remains - the
K/T asteroid came nowhere near wiping out all animals and plant species. We
took this hit, reeled a bit, and got back to business relatively quickly.

In the 500 million years of animal life on the planet, the most
consequential extinction of all was at the end of the Permian. This event
resulted in an enormous amount of extinction, but came nowhere near to
eliminating animal and planet life. For all of its wreckage, within ten
million years the world had caught up to its prior biodiversity, and then
surpassed it. But there is no credible evidence that this extinction was
caused by an impact.

Over the past decade a new truth seems evident: instead of finding ever more
mass extinctions of greater severity, we are finding fewer. The so called
"Big Five" - the mass extinctions of the Ordovician, Devonian, Permian,
Triassic, and Cretaceous - have been whittled down to a "Big Three." New
work by Mike Foote and his students at the University of Chicago suggests
that the first two of these events, while undoubtedly major crises of some
sort, were not in the class of the later Mesozoic events. My own new work on
another of the so-called "Big Five," the extinction at the end of the
Triassic, also suggests that it was never a threat to ending animal life on
the planet. The K/T event seems unique. None of the other major extinctions
appear to have been wholly or even partially caused by impacts.

This is an excellent rebuttal to the nonsense spouted by BP, GB, and EG and supports what I said in my initial response (without having read the article) in far greater detail. I wish I had read the article first and just quoted these guys to avoid having to deal with several grossly erroneous replies.

Why are so many so confused?
Mark

PS: I do however question Ward on the no credible evidence for a Permian Impact. Last I heard there was weak evidence. Perhaps he considers it not credible because of the absence of the markers used to establish the K/T impact.