Geez...it's hard for some guys to admit they were wrong...LOL. It is not a still photo but the line was drawn actually on a moving picture via V1 programme tool, thus, it is pretty accurate.
The theory is not controversial, IMO. Even Hogan mentioned that the downswing plane must be shallower than the backswing one. The loop happens unintentionally thanks to subconscious mind and the explanation why it happens is a bliss for everyday's hackers who are constantly being cucified as OTTers and usually end with severe goat humping, poor pivot, loss of power and uncontrollable shots.
Cheers
Yes I think you will relate very well to not liking admitting you are wrong.LOL
Post the entire video and then superimpose that line you have drawn on it and lets see if they match.