The idea is that as a programmer, you have to have an intimate understanding of what is going on in order to make the machine do your bidding quickly and correctly.
But that mediocre Eclipse user I caricaturized does not have that understanding. He certainly knows how to get the job done for a certain set of tasks, but he does not know the details of how this is happening. Thus, he creates programs that follow "best practices", "conventions", "design patterns" and lots of automatically created wizard-boilerplate.
That might not be "bad code" mind you, but it almost certainly is not "great code", either. Thus, mediocre. And then these people create libraries that are mediocre and try to use only libraries that they can understand and that are hence mediocre. A culture emerges that is very consistent, but also very mediocre.