Is he wrong?

Sure, he is (in my own perhaps prejudiced view, at least). The possibility to create new operators is a tremendous way to extend the language and to make it able to face the challenges of the years to come that we can't even think about today. And there are many other features to enable you to extend the language.

Criticizing this way the details of an example presented for pedagogical purpose is just a lack of intellectual integrity. I'm not going to discuss it further.