I do really hope nobody is reading that article thinking about prediction. It's completely full of weak proxies that will lose any predictive power as soon as they are used.

(And that's also why you care about causation even if you are only looking for prediction, because you don't want your proxies to change their meaning as soon as you act on them.)

It is indeed full of correlation that can unmask interesting facts if studied further. And the GP complaint is meaningless if viewed from that angle, so I do really think he was talkinga bout causation.