[Mithadan]

Yes, it's off track and may be worthy of a separate thread. Nonetheless, I'll take a shot at this.

Wow. Pure speculation at this point. Gandalf is a Maia affiliated with Lorien, who drives dreams and perhaps insight and understanding of the peoples of Middle Earth. Gandalf is wise and insightful. He can inspire those in need of encouragement. In my view, Gandalf can distinguish between evil and good, not because he is capable of evil, but rather because he is capable of understanding it.