Sorry your experience was such a negative one.
As one of the editors who reviews applications, however, I'd like to explain a little of the "other" side. Let me begin by emphasizing that none of us want to discourage people from applying. We want good editors -- and lots of them.
But we don't always have as much time as we'd like to devote to the project. We're all volunteers -- with jobs, families, commitments, etc. Processing a single application can take anywhere from a few minutes (in the case of a really bad application that's an automatic reject) to two or three hours (in situations where an applicant appears to have some potential). And while the number of applications we receive on any given day varies, the number always exceeds the number of reviewers -- usually several times over.
Writing a customized response takes anywhere from 10-30 minutes, depending on the situation. Initially, that doesn't sound like much, especially when one considers that an applicant may have spent three or four hours completing an application. But the applicant completes only one application. It's not uncommon for a reviewer to process a dozen or more applications in a single sitting. Sometimes, it's mathematically impossible for us to write personal responses and still process as many applications as we need to process in the time we have available to edit. At other times, real life intervenes. There have been a few times I've rejected without feedback because I suddenly got called back in to the Job That Pays The Bills, or because the baby woke up, or because the dog needed to go out, etc. Especially in instances where one of us has spent a great deal of time reviewing an app, we don't want to throw our work away and leave it sitting in the queue just because real life beckoned.
If you truly want to be a part of this project, please take time to read the editing guidelines, available at http://dmoz.org/guidelines.html. Look for a small category (fewer than 100 listings, including listings in any sub cats). And give it another shot. We do need and want editors, even if it is humanly impossible to write a personal response to every application.