I suspect it's a need to be the smartest person in the room. A lot of people are long Tesla, a lot of the same people are optimistic by temperament, taking a pessimistic view is an easy way to stand by your reality-filter and look smart if you turn out right.

Then the filter does its job and makes them blind to the kind of things you've pointed out. The only way for this to change is people to get skin in the game so that it hurts when their theses are proven wrong. I wonder how many of the people alleging fraud are actually short TSLA.