The experiment is not 'false'. It is what it is. McIrishman does a comparison of two swings one with more trail wrist flexion than the other. It is simple to come up with a physics based rationale for the one with more flexion producing a faster club head speed at impact but that would be a hypothesis not data. The data is what it is. If other people do the same thing and get different data that does not make their experiments 'false' (assuming they actually do the same thing). It's just data and it is what it is.