In the very immediate aftermath and without the benefit of replay this was my opinion too. (And expressed with an equal lack of class).
But after watching the incident a few times, and with the benefit of hindsight, it's pretty clear that he was disorientated.
We shouldn't underestimate the impact of having one bloke grab you between the legs, and with the help of two other 100kg men, lift and then twist you somewhat in the air at speed. It would be both disorientating and frightening.
Hence why he made the miscalculated decision to tuck his head in. It was clearly intentional, but was due to disorientation and an expectation that he was about to be lifted well above the horizontal. Unfortunately he wasn't, and as a result his decision to tuck his head in saw his neck crushed under the weight of four bodies.
As for the tackle, I still don't think this was even close to the worst lifting tackle in that game. It was just a freak accident and if it's anything more than a Grade 2 then we'll have a lot of players suspended this year, including another 4 or 5 out of that game alone.