Using a rhetorical question to make a point in an environment where anyone can edit, like, say, a wiki, is a blunder. Rhetorical questions are a perfectly valid way to make a point, but that question mark at the end is just completely irresistible for some people. They have to edit in an answer.
Maybe people should refrain from answering rhetorical questions. The fact is, though, that they don't refrain. The good thing here is that there is an easy fix: Don't get the whole thing started by using a rhetorical question unless you immediately answer it yourself.