It's because it isn't "predicting" anything, but rather aggregating user feedback. That is of course going to be closest to judging the subjective "best" model that pleases most people.
It's like saying how can evaluating 5 years of performance at work be better at predicting someone's competency than their SAT scores.
It's like saying how can evaluating 5 years of performance at work be better at predicting someone's competency than their SAT scores.