You make a good point. There are many situations in which it's fairly obvious how the comparison ought to be made: the human should not be allowed to use a horse in competing with the horse in "running", and should not be allowed to use a computer in competing with the computer in "guessing sexuality". However, if the competition is in "predicting share price movements" then surely it would be strange not to allow some kind of computational assistance for the human, so in those cases, at least, it gets a bit hard to decide where to draw the line.