But the probability of the latter's bringing life as we know it into existence is a crucial factor in the debate that you can't just wave away.
Yes, you can wave it away. RAZD demonstrated that the calculations were done terribly incorrectly. The subtext is that those who publish such junk math have had a lot of time to pass this by a real statistician and since this sort of stuff is still being published without correction someone is
deliberately supplying bad numbers.
He also points out that done as correctly as possible or not they still can not have any meaningful bearing on the debate since we don't know enough to do a meaningful calculations.
If you don't understand what was presented then you are simple not in a position to comment on the issue at all. The material presented was very straight forward and screamingly obvious to someone who has had an introductory stats course. The sources of the original probablity calculations are either not at all competant or dishonest (unless you can think of another option).