I will forward this on for SE to think about improving.
The question may not be answerable, but it doesn't make the question wrong. The question is nothing more than an expression of the users query or intent.
For example, unanswerable questions could give a stack listing if relevant answerable questions.
But it just seems wrong to take highly targeted inbound traffic and send them to a page which basically says 'nothing to see here'.
Or, quite often, substantial positive votes, and the wails of a legion of users protesting the closing. I would guess that that kind of question is more likely to be the target of enough inbound links to lift it into the search results people actually see.
Marking closed, zero- or negative-voted questions as noindex might be a good move, though.