And after cursorily dismissing them they just say "therefore, it's an aesthetic meme. This is just what perfect hands look like, sorry."
A hypothesis that was not considered, for example: 'We asked people at school to imagine that they were going to be sitting still for the next three hours on a stool, and to sit on it in a way that was perfectly relaxed. We then prompted them "remember, in old times you'd have had to sit here for three hours, really relax." Finally, we then picked up their left wrist, turned it, and placed it on their chests saying "great, now can you just hold this hand here," and took a photograph. In 30% of these photographs we also see, even without syndactyly, that the two fingers get forced together just by the process of having your wrist twisted by an artist and then the fingers having to conform to the contours of the chest.'
I don't know what that percentage is, but I'd be surprised if it were 0%, right?