Dear Dr Kaczmarek,
I will presume to interpret Arthur Rubin's phrase "senior editor". I believe that his intention was to communicate 1) that the editor in question was, in Arthur's opinion, more experienced than himself, and 2) that it wasn't a whim of a new-fledged editor but the decision of someone with several thousand edits under his/her belt.
I read a lot of questions and comments in this forum, and I also do a lot of editing and participate in the editorial discussions, and though I wouldn't say that the ODP is ideal and problem-free (it is, after all, evolving all the time) there is one misconception that many disgruntled webmasters appear to live under and which simply isn't true: that the ODP is hopelessly corrupt, whether by power or something else. To quote yourself:
the “senior editor” is always right; you cannot know his motives and criteria or even himself; if he says you are wrong, you are wrong; if he says you are out, you are out. The real name of this system is, of course, censorship.
Not many of those points are correct, as a matter of fact. If they were, it would be abuse of power. However, senior editors (among whom I think I can count myself these days, even though I'm junior to a great many editors) are patently not always right. All edits are logged, and senior editors are as answerable as their more junior colleagues for abusive editing. And senior editors do make mistakes, and are called on them. The nice thing is that mistakes in editing are not irrevocable. Anybody who has the editing rights in a particular part of the directory can add a site that was mistakenly deleted, or delete one that was mistakenly added. And the editing criteria are official.
Furthermore - and this is important - anybody can become a senior editor, provided they show enough competence. If you make 500 brilliant edits a week and keep your categories in meticulous order, it doesn't matter if your motive in becoming an editor was to promote your own site - that's not part of the equation. Only your work as an editor is. And finally, it takes more than just a whim of a "senior editor" to remove another editor. The community of editors who have the power to decide that - the Meta editors - are as diverse a group of people as anyone could wish.
The ODP is not a powerful force, nor does it influence peoples' lives in any important way, save possibly for the way it makes people give up large chunks of their lives to editing, but people do that for their hobbies. With your background, you should know that "censorship" is too serious a term to be used in this context, even if it were applicable.
Yours sincerely,