1) You receive hundreds of spam applications even if you mention explicitly code-related stuff - like GitHub/Bitbucket repo, years of programming experience, know-how in TDD, we sometimes experiment with continuous integration experience or others. The wave comes as long as you mention WordPress.
2) Other than the spam applications and standard "bots", many people simply don't know what's included in "developer" or what real "developers" do. Even if they do want to learn and get better, they don't know the limits and can't aim higher than they are.
All I can say is, personally, my own professional ethics require me to try to know my own limits and abilities and present those honestly. So, for example, if a client came to me with a technical need, and I felt that I wanted to fulfill it, but it was reasonably out of my wheelhouse, I would either turn down or direct that client to the best alternative I could think of, if I could not provide it.
I suppose, ethics training is a part of professional development in more rigid occupations, maybe if ours was formalized more, this would be more prevalent.
Based on your need as an interviewer/organization, you may choose to accept someone who shows passion but less refined skill with a learning opportunity, or you may require someone at a high skill level ready to go on day one.
To me, this is the interviewer's responsibility, to know their requirement and make it clear to candidates.