Curious to know, he found a few papers where the conclusion was drawn improperly to the statistical study, but he offers no counter statistic.
He has found 7 scientists that say they were misclassified (who knows how many he actually contacted, he doesn't provide that information.) There were 12,000 papers examined in the original study. There will always be errors, which is why the sample size is so large.
So I guess the better question would be, what does that author believe the true number to be? 95%? 92%? 40%? Or is he only trying to discredit the paper without offering any additional study on the topic?