I agree. I don't know if they've covered their short position last year from 270, but if they haven't, this could be an attempt to let them cover at a lower price.
As with many short attacks, they attempt to leverage any perceived negative news into something quite out of proportion. In this case, I think they are working from weakness regarding estimated Model X deliveries, using it as excuse enough to go on the attack, and in the process they throw in everything including the kitchen sink.