I'm not against camelcase and its variants, but there are a wide variety of naming standards using caps, it's quite possible to get mixed up between them and introduce ambiguity or worse (referring to the wrong variable).
If you had a naming convention which prohibits vowels, then the identifier "shrt" is ambiguous because it could be "short" or "shirt". That doesn't mean that "short" is a bad name for an identifier.
What is funny is that reading it will hardly make me or you a better programmer because most of this things will take anyway years to be fully understood / mastered, and of course it's an endless process of refinement.
But still very useful to read what we should try to focus on when writing good C code.