Doesn't matter why he spun in....its that
he had insufficient height above the hard
stuff to effect any sort of recovery - let
alone a safe one.
From what I saw on the vid he had large
right rudder, up elevator, and in a (what I
believe to be) climbing turn. All a perfect
set up for a spin entry.
Also I see there was no basic instinctive
opposite rudder from the incipient to the
impact - though it looks like he'd relaxed
the elevator. But probably he didn't have
time to even **** himself.
Reckon he overestimated the effect of
the slats.