It's a problem all over, not just here. Not five minutes ago I voted to close a programming question on Web Applications. And how about all of the "how do I fix this non-programming Android issue" questions that have been closed on Stack Overflow? (And believe me, there have been a lot more of them than development questions here.)
There are any number of helpful hints to guide potential Askers to the right place. You probably don't remember because you've been around for a while, but there's a dialog that new users need to click through before posting that says basically: I have read what this site is about, I see it again here right in front of me, and this is the right place, so let me ask my question. There's the FAQ, of course. And the "Ask Question" page does give guidance, at least until your reputation meets a certain threshold.
The problem, and it's not limited to here, is that people don't read on the Web. The only thing that keeps sites on topic is swift, efficient, ruthless moderation when people post off-topic stuff. (Remember Usenet?) That's because people will post off-topic stuff; it can't be stopped.
Don't forget, we also have the development tag, which has been left on here as kind of a "honeypot" to make it easier to find off-topic questions. (The assumption being, of course, that anyone doing development would see that tag and use it, in spite of the tag wiki excerpt explicitly saying that such questions are off-topic.) Unfortunately, the applications tag (which is terribly misused and abused and is in dire need of cleanup) is almost always one of the sample tags suggested and, since they're developing an application, must be the tag they want, right?
So, yes, it's annoying and I wish these people would get a clue. Don't worry about the Moderators' time, though. We don't need to waste it with simple stuff like this. Just continue to vote to close. Downvote them for wasting your time. (Enough downvotes—six, I believe—and the question drops off the front page.) If you're feeling kind, point them to the FAQ.
But you should probably resign yourself to the fact that no matter how many clues and help and speed bumps we put in front of new users (and there are quite a few), some people are going to post off-topic stuff. All we can hope to do is educate them, hopefully educate people who see their off-topic question and so won't repeat the mistake, and close them down without mercy.