Why do trolls make their Q&A's private?!
Answers: It's probably the same reason as your's.
You'd think that that they would want you to find their questions! So that they can annoy the most people. If I were a troll I would not make them private. I make mine private so that I get different people answering my questions.
By your logic ... you are a troll and thus are in a better position to answer your own question than those of us who reveal our Q&A's . . .