I’ve been thinking about this too.
First, because it looked so different than other energy bending we’ve seen (who can forget the visually stunning red/blue inner-light battle at the end of A:TLA?) and it seemed to “walk back” the bending abilities. Assuming that channeling lightning is more difficult than fire bending, Amon’s technique looked more like “draining” as final spurts of lightning, then fire came out.
Second, if I may geek out…
Energy Bending and Chi-Blocking are similar in the sense that they skills essentially useless as an individual activity. They require contact points with chi centers. The Lion Turtle passed on knowledge to Aang through the forehead and chest chi points and Aang took away The Fire Lord’s power with the two face contact points and the chest contact point. Amon had a grip on the neck and seemed to only need his thumb on the the “third eye” region of the forehead.
Overall, I’m wary of calling this Energy Bending because it looked so much different than the Energy Bending we’ve seen before.
I agree we don’t know about “afterwards” but the show certainly wanted to nail home that Amon was boasting he could permanently take away the powers. So regardless of if it’s true or not, at this point in the narrative, I think we’re just supposed to be fearful of this mysterious power.
If you’re conjecture is true, though, I wonder what the Triple Threat Triads would think about being made fools of.
-Da7e-