Fine, let's go with that. It should be easy to see, that shorts are confident that the stock will trade lower. Otherwise they wouldn't be short. So why would they try to talk down the stock? The same logic is applicable there.
If you believe, that it is possible to simply talk the share price of a big company up or down over a prolonged period of time, who would have the bigger incentive to do so? That Jim Chanos guy has about $2b assets under management, quite a bit is in long positions and usually that money seems to be scattered among dozens of different investments. I'd be really surprised to learn, he has put more than a $100 million or so in a Tesla short. The bigger institutions own between 1 and 4.5 billion in Tesla stock. Where are the accusations that those guys prop up the share price? Let's just assign a value of $30b to Tesla mobility. I mean, why not? For some longs it seems to be completely unthinkable, that Mr. Musk is saying things every now and then, simply to help the share price before a capital raise or get a bond deal done.
Now let's look at the smaller fish for a moment, shall we? If you read TMC only, it's obvious that guys like Montana Sceptic or other shorts on Twitter and SA are lying all the time, making up stuff to influence the price and are probably paid by somebody else. It's often regarded as improbable, that those guys are honestly convinced of what they say. It has to be some kind of evil cabal, since every person opening their eyes can clearly see why Tesla will prosper. Shortie has been wrong with his assumptions! He's a liar! And an idiot! At the same time, people like ValueAnalyst or Victor Dergunov have been quite wrong with some of their past projections too, because ... well, projections are hard. Everybody gets it wrong from time to time.
Why is it like that? Imho, the same level of criticism, scrutiny, trust and goodwill should be applied to both sides of the trade. Everything else leads to bias, which is just a milder form of self-deception and usually not a good thing.
I would think overleveraged shorts may get the same warning call? I've seen this sometimes with european brokers, when they expected higher than usual volatility after certain events and they've been raising margin requirements for shorts and longs. (The Brexit votum comes to mind) ... It's not hard to imagine a polarizing and volatile stock like TSLA can lead to a lot of margin calls, if you are on the wrong side of the trade and enough people panic.