So, then, even if I were to apply to be the editor of that category, there's no guarantee I would get it?
I would have hoped THAT would go without saying. But yes, there is no guarantee.
>Even if otherwise qualified? Because the current editor is just neglecting it while he works on other categories?
OK, maybe this is a clue to your particular form of misunderstanding. We focus on demonstrated skills (see, I can do something pro bono, and I'd like to do something for THIS topic; see, I can find good websites, and describe them in good English.) This isn't rocket science--some sixth graders have done fine editing work, and you don't need professional experience to build most categories. (I have hardly ever edited in the areas where I DO have professional experience.) But these are not universal skills either--many glib oral communicators really can't handle the objective, information-rich style required. (I'm the other way: I really can't do the glad-right-hand-and-left-hand-in-wallet spiel.) No amount of paper qualifications can hide that fundamental distinction in the substance of communication.
Now, how do we tell the current editor is neglecting it? Simple. We all know he isn't. Because he doesn't exist. There is never a "the category editor." Never. There is no such thing.
So, how do you tell if ALL the editors are neglecting a category? Simple: see if you can find lots of good sites that aren't already listed.
So, your application to be an editor is the challenge -- you assert that there really IS work to be done in the category, and as evidence you show several good sites not listed.
If nobody can do that, or if nobody cares to do that, then by definition the topic isn't neglected. It is receiving all the attention justified by its body of knowledge and its social importance.
This perspective is broadly useful in dealing with any number of extremely complex prioritization issues. It is unfortunate that it is so seldom used.