Fireman,
I presume you are referring to Jensen Huang? If so, the difference between his position and Dr. Missling's is that a company like NVIDIA is generating revenues, coming out with new products -- basically it has a pipeline that can support its growth, so shorting it is a risky proposition in both the long and short term.
Anavex, on the other hand, has no revenues. It has a promising drug that is still early in the FDA approval process. Someone who wants to short the stock knows there is no immediate long term risk -- the company only really busts out when FDA approval or buyout happens, and the likelihood of either taking place at this stage in the game is minimal.
Missling could dare shorts all he wants. But at the end of the day, even the best news will create only a temporary spike -- look at the past price action. Then, as people realize that the news is good but it isn't game-changing from a revenue producing perspective, the demand lessens in the near term and shorts jump back in.
One day, hopefully, Missing will announce that there's either a buyout offer or FDA approval. That will be the final nail in the coffin for anyone who was willing to short this. On the other hand, shorts believe with just as much conviction that Missling will one day announce that it was a valiant effort but Anavex didn't succeed, and now it's back to square one.
What I am trying to say is that while Missling might not be handling this perfectly, and I do think his compensation package is a bit higher than it should be, he isn't necessarily in a position to go on the offensive because he doesn't have the ability to back anything up. All he can do is say, "wait and see what happens" but even he doesn't know how this will play out in a randomized blinded trial with 300+ individuals.
NVIDIA, on the other hand, has a product that it knows will sell. Its CEO can make threats and be more aggressive because all that is required to change his situation is better marketing. Anavex doesn't yet have a product to market.
Stay safe out there!