"PS We get 15 hours flying training (used to be more) and many hours of lectures (and part of several exams) on aircraft characteristics, physics of flight etc. How much does a CPL holder have to learn about ATC?"
ATC is in the service industry, here to provide a product to pilots not the other way around. That said, pilots don't know as much about the ATC system as we could. However the nature of the relationship requires you know more about my needs than me of yours.