I believe that John Carmack's argument considers both the semantics of code and reality of programming languages (here, C/C++), while the OP only considers the

I believe that John Carmack's argument considers both the semantics of code and reality of programming languages (here, C/C++), while the OP only considers the former. Ideally naming things without any additional problem (for example, as others noted, extracting a block of code into the global scope violates referential transparency) should be easy, but many languages don't. Carmack is using a comment as a means to give a name without introducing unwanted abstractions.