Just to dispense with the polygraph discussion, (though I doubt it will, perhaps if not the mods will see fit to split the thread), it doesn't matter if the polygraph is not good enough for court, because the majority of the answers would be correctly determined. Therefore the claim ALL 100 atheists were lying or all the atheists in the above story were lying and really believe in gods would not be entirely discredited on the basis of the polygraph reliability alone.
But we can't "dispense with the polygraph discussion". That's how mayday claimed the results were obtained: By using the polygraph only.
If you don't discredit the result on the basis of the reliability of the polygraph alone, what else are you using?
Here's a very thorough evaluation of polygraph testing. THE POLYGRAPH AND LIE DETECTION; Committee to Review the Scientific Evidence on the Polygraph; Board on Behavioral, Cognitive, and Sensory Sciences; and Committee on National Statistics; Division of Behavioral and Social Sciences and Education; NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES and on this page is a graph of results showing The entire report is available at the link.
Please explain, in your own words, what the results show.