>On DMOZ, I have absolutely no idea how any of the administrators decide to accept or decline a website or simply to never, ever, respond either way about it.
By the way, it's "editors", not "administrators". We're doing work, not bossing anyone else. There is a huge conceptual and practical difference there!
But if you want to know how editors decide to respond, it's very simple. Because so many webmasters are such violent and vicious jerks, editors are strongly recommended NEVER to respond.
And if you want to know how editors decide whether to accept or reject a site, the guidelines are publicly available. Anyone can read them. But mostly there's no need, because it's pretty simple also: unique information, accepted; hardly any unique information, rejected.
If you want to know how editors decide what sites to review first -- that too is simple. Every editor makes the decision based on any criterion they want, so long as it doesn't unfairly promote their own sites.
As to your feeling "blacklisted" -- that is irrational (although perhaps a weakness to which extremely self-centered people are prone.)
Stand back a moment, and think. Yours is not the only site on the web. There are others. And if you can ever attain that perspective, then you can start putting basic sixth-grade arithmetic to work. How many others are there, and what's the chance of any particular site being one of those reviewed tomorrow?
Editors are going to review 5 thousand or so sites tomorrow. There are maybe 100 times that many sites that have been submitted. So all other things being equal, you have about a 1% chance of being reviewed tomorrow. That chance is obviously greater in smaller categories (where we need more sites to be comprehensive) and much smaller in very large categories (where the sites we already have would keep any surfer busy for years.)
Now, just because you buy a lottery ticket and don't win, does that mean the Lottery Commission has blackballed you? That would be nonsense, absolute nonsense! Most people don't win. With the lottery, you pay again tomorrow. But with the ODP, your ticket is good until you win. And every day, there's a new lottery. Most site submittals don't get reviewed; but a few (few thousand, or few percent) do.