Alright this just came to me while I was chatting with a friend about Zuko's son Iroh the general for the United Forces, when I told her that Amon had taken over Republic City basically it dawned on me that Amon only touches the mind of the person he's taking the bending away from. What if he doesn't really take their bending away but he just does some kind of memory wipe. In the terms of that Lightning firebender, his body knew the moves after years of doing it but his mind just couldn't recall how to fire bend. Maybe that's how he plans on making the whole of Republic City be to him "normal" Make all the benders forget how to bend. He hasn't truly taken their bending they just think he has because they can't remember HOW to bend.