I see I'm one of the guilty parties. I suppose that puts on me some onus to explain.
Take a look at this question, which is also a total newbie question, and attracting downvotes and close votes as we speak (and it probably doesn't help that the author chose the username "nobrains"!).
But I think this is a good basic question. I've upvoted it, and I won't be voting to close (at least, not on the grounds of "minimal understanding" or "professional sysadmin").
Why the difference? Because the DHCP/MAC question betrays utter ignorance. There's no subtlety underlying the right answer, just spoon-feeding basic information to satisfy the OP's total failure to have read anything about the field. The www.
question, on the other hand, skates around a genuine subtlety in the DNS which can catch people out big-time down the road.
Mark, you have a diamond, so you really do get to speak for the community. Nevertheless, when you write "This might be obvious to a network administrator, but in a highly compartmentalised IT department, if you've spent your entire life dealing with a mainframe connected to dumb terminals, and you're suddenly thrust into setting up a cluster, you might have no idea" I get very nervous. Are you suggesting that SF is available for people who are professionals in one aspect of sysadmin, so they can ask n00b cross-training questions, but not to people who are, say, developers, who also want to cross-train in exactly the same way? Because I can't follow you there, I'm afraid. For me, the "minimal understanding" close reason (which you say you don't like - but nevertheless it exists) means that on the subject on which you have chosen to ask a question, you are expected to have acquired a firm grasp of the basics already.
Once, when a newly-fledged sysadmin, I was listening to Eric Allman talk about some of the subtle gotchas in SMTP (he's a very good speaker, by the way). In response to his rant about the problems caused by envelope-recipient vs. header-recipient mishandling, I asked why we had to have both recipients. For my query, I got only a withering look. Once I had admin'ed a mail server, and understood why we need both kinds of recipient, I understood the look, and wholeheartedly approved of it. The check it gave me has helped remind me many times since that I need to line up my ducks before invoking "big gun" assistance.
If SF is not to sink into the mire if general ignorance, I feel it needs to maintain in all its users an attitude of "I'm going to a wellspring of experts here; I need to treat it with basic respect". Otherwise I'd just go and hang out at YvahkDhrfgvbaf.