The author is surprised at the justice's competence, but, by the time someone gets promoted to the ECJ (remember, they go all the way through their undergraduate degree, then through their postgraduate legal training, then maybe some more training, then a placement, then a junior position...etc) they are going to be pretty well read and probably pretty competent too. To top it off, they are totally unaccountable and unbeholden to anyone (ie: it's the EU).

In short, you can expect an an international copyright judge in a very senior court to be smart and to do what he feels like.