So if even one editor makes a mistake and rejects a website, and that website owner is not notified, then where is this website owner supposed to go to for help?
The website owner can go wherever he wants for help. But there are places where he's not likely to find any. The local Shriner's Hospital, or Baptist Church, estimable as those organizations may be, are not likely to give much help with website promotion! And there is no reason the Open Directory volunteer community couldn't have its own mission completely unrelated to any particular website.
But here's the more important issue. Suppose a website suggestion is reviewed, and the reviewer doesn't find anything on the site worth listing. What are the chances the reviewer missed something? (about 1% in my experience). What are the chances the suggestor really wants the site listed (um, 100% more or less).
OK, so out of 100 suggestions considered useless by the volunteer, there will be 1 mistaken editor and 99 mistaken but impatient webmasters. And the more impatient the webmaster, the more likely he is to be among the mistaken.
Those are not good odds. No sensible editor would enter into long justifications of his activity when the discussion would be a total waste of time 99% of the time for obvious reasons, and a total waste of time the OTHER 1% of the time for more subtle reasons. Look at it this way. If an EDITING mistake is made, any editor could simply re-review the site, if there were some evidence it was worth listing. There STILL would be no need for any discussion with the webmaster, long or short. The website is there, ANYONE can just LOOK at it.
And what could the editor tell the webmaster that the webmaster doesn't already know? "Your site don't have anything at all about the Socioeconomic ramifications of disestablishment!" ("Yes, I know that.") "And it doesn't have anything about the life cycle of the pileated morganser!" ("Yes, I didn't know anything about that!") "And the stuff about Romanian politics is cadged from the CIA website!" ("Doh, yes, I know that, I'm the one who cadged it, what's your point?") "Do you really expect a list of all the unique information your website doesn't have? How fast can you read?") ("No, what's your point?")
"A reviewer couldn't find any unique information on your site!" That's all that matters, and the webmaster should already know how hard it is to find unique information--it's his own site, he knows where the information came from, and if he's not ignorant and unteachable, he has a good idea about what information is on other similar sites.