SE has good rules which keep questions relevant. I would say that if the question is closed and there are no existing duplicates, then the question itself doesn't have much value. ( There are of course outliers. )
There is a misunderstanding here, moderators on SE don't actually close most of the questions, normal users with privileges to do that, do so by voting. So such a question doesn't have value because users decided so, not moderators.
The last paragraph shares the misconception with the previous one. Users vote on and close question. Inf fact moderators are so rare on SE, that they only do critical things that should not be trusted to users, which do the rest.
Not fitting the guidelines of SO and not having much value are two very different things. Are you sure you meant the latter?
[1] http://stackoverflow.com/questions/4674609/looking-for-a-ric... (not my find, posted in another comment on this thread)
Having strict moderation standards is SO's business. I may or may not agree, but it seems to work for them.
Leaving closed questions, particularly those without answers, on their site sucking up google juice and deceptively appearing in my search results is scummy. If they don't want it on their site, they should ask google not to crawl it. And that goes squared when the question doesn't have an answer.
To a person _arriving at SO from Google_, "moderator" and "normal users with privileges" are basically the same thing, even though they may be technically different. And, those "normal users with privileges" tend to be overly aggressive when flagging questions as "off topic" or "opinion-based".
While I understand the intentions of the moderators, they seem to assess the value of a question for people at the moderator's own skill level than at the people who might be asking the question or seeking an answer to a particular question.
The silver lining for me is that at least they don't delete the questions and answers they mod down. I've found a lot of useful stuff in questions that the mods didn't like.