Uploading Wordpress, using standard themes and installing plugins isn't development, it's admin.
On the other hand, building custom themes or writing custom plugins is web development.
Doctors are all doctors, but there is a difference between a family doctor and a neurosurgeon. Lawyers are all lawyers, but a patent attorney is not a criminal litigation specialist.
It is fine to have a generic term for a broad profession, then get more specific if and when it matters.
Perhaps, though, I can still refer to these people as "developers."
At my company where I'm the back-end guy, our front-end guy does most of the Javascript, but he has to get my help whenever he has to do anything non-trivial. Only a few projects a year ever has him needing my assistance.
Most companies' Javascript needs should be similar. Every once in awhile there will be a marketing push wih non-trivial Javascript needs, most of the time they can get by with basic jQuery. Hide this element, show it when there's an event.
Unless you're working for a news agency, making Snowfall every month, I'd be surprised if the business actually did need more. Of course, if the front-end guy decides he has to learn React, well, I'd say, go ahead, knock yourself out. But don't kid yourself into believing it's really necessary.
Sure it is. I know people who make a living at setting up Wordpress. They do it very well, and they work hard at it. They do design work that I cannot hope to match. And they do it all without writing any more code than some HTML and CSS.
I'm not going to insult them by saying that they are not developing web sites. They absolutely are.
Coders do not own the label of "web developer". Because that is all it is -- a label.
Call yourself whatever you want to call yourself. Let others do the same.
FWIW, when people ask what I do, I no longer get specific. I just say, "I write software."