I think spenrose is saying “We shouldn’t be upvoting this” or maybe “I hope newspapers don’t report on this like it’s a clear, solid answer”, not “This paper is flawed in ways that the authors didn’t recognize”.
Personally I’m fine with this being on HN because I think this audience understands issues around low N (and commentators do a good job of pointing them out), but I agree that it would be problematic if this were picked up by the New York Times or something.