Back in the Alpha I noticed, in the P51B for one example, that I could induce an accelerated stall/unrecoverable spin by tightening an already tight turn. My attempts to recover (three turns - opposite rudder) resulted in a secondary spin at low altitude. Crash.
This was observed by a squadron mate.
I went to work on my sticks and have been subtly tuning them for the last weeks. Successfully.
The video is similar but not the same as my experience. Not to feed the conspiracies, the Tiffie did some things that I don't recognize as a spin recovery, though he appeared to spin after the first 'snapping' event.
Since a snap roll is a legitimate defensive maneuver in some instances, it needs to be controlled. This looked like stick stirring to me.
Just my opinion.