I don't think the titles we use are irrelevant like some have said, but why draw the line at the manual editing of text that is ultimately translated into machine language? Do programmers working at a lower level of abstraction have a stronger claim to the title of "developer"?

I've never used WordPress, but to my knowledge this is just a tool that reduces the amount of manual coding involved in creating a website. To me this seems similar to the way Python reduces the amount of C you have to write, which reduces the amount of assembly you have to write, and so on to the machine code. Perhaps WordPress "development" is considered easier, but even if you equate the terms "developer" and "software developer," it doesn't seem like an unambiguously inaccurate or misleading description of the activity.