I know the answer to this now. My question wasn't closed for any single reason or because of any single rule. It was closed a bunch of reasons:
- There are loads of people with the power to close (law of numbers).
- Those people don't have to answer to any higher authority, so they exercise their power more lightly than they would otherwise.
- They feel good when they're being decisive and particularly when they criticize someone else. They look for reasons to separate themselves from other people; why they are better SO community-members. So they look for reasons to close, not reasons to keep open. And once they start looking in that one direction they won't change their mind (that's just how it works for people, they don't want to admit they were wrong).
- There is now an established culture for closing so people feel confident that closing is a safe decision.
- They haven't learnt to use a light touch, in leadership.
People here have tried to answer why my question it was closed but I now think that's kind of funny. Some of the answers were really bad. Even from people who write well and sound really intelligent.
I think at the heart of the problem is this drug called "reputation". It's actually addictive! You make those numbers so big on the site. And now everybody is clamoring for it like popularity in high school.
Once a question is closed the justification hats go on and people put all their mental effort into convincing themselves that the right decision was made. "Surely, it must have been right because that's just how we do it here!", they're thinking. What would happen if people put all their mental effort into actually objectively questioning the kinds of motivations/decisions that influence such outcomes?
Of course the questions you really need to ask are difficult so people generally avoid asking them:
- What is a question?
- What isn't a question?
- What is a vague question?
- Do vague/difficult questions really harm SO?
- What direction does SO want to move in?
- What constitutes a healthy community?
- What psychological effect do we need to be aware of?
- How will people feel when we do x thing to them?
- Why are duplicate questions closed?
- Do those reasons apply to second attempts to ask a previously close question?
So, how could the situation be improved.
- Fewer people with power.
- People who have the power being more careful. They should routinely discuss how they use it.
- Power being granted to those worthy of it.
- More detailed rules on what constitutes acceptable and unacceptable questions on Stack Overflow.
- Constitutional rules codifying the what SO aims to achieve and the direction it wants to move in, including the kinds of attitude it wants to foster and the kind of experience that it wants people to have when they come here. (I certainly don't believe this question has been sufficiently answered, otherwise when I came here to ask why, you would have all pointed me to specific extracts of a document that was guiding you and told me how it relates.)
The guise of SO being community-driven isn't serving the community. It's very glamorous and web 2.0 and everything but when you put power in the hands of the masses you get all the problems to do with psychology that I've outlined. Most people prefer not to think hard about decisions unless made to and, if everyone leads, nobody leads.
I've now had a number of annoying experiences on this website, which sucks because I really want to like it. I'm not sure where I want to go from here. Maybe I just need to learn what is acceptable. (Shame there isn't really a good definition of that.) Or maybe I just won't use Stack Overflow. I know in the past I've spoken-up about things, like this, and it has turned out, afterwards, that there were actually a lot of other people who felt the same way but didn't speak up.