Correlation doesn't imply causation. How is that still so hard for some people to grasp? His entire argument is invalid because it's based on that simple fallac

Correlation doesn't imply causation. How is that still so hard for some people to grasp? His entire argument is invalid because it's based on that simple fallacy. The selection process will obviously skew any results in favor of colleges. It's the same as trying to argue that playing for the San Francisco Giants automatically makes you better at baseball. Is that really the case, or did they just do a good job of picking players who were already the best?