Matt Levine has talked about this, too
Edit: got distracted but here's his link: https://www.bloomberg.com/opinion/articles/2018-02-09/can-no...
Also, I hate amp
Here's the relevant bit:
> "Wait," people ask, "how is it not manipulation to short a stock and then publicly announce that the stock is bad?" I am always confused by this complaint. Just flip it around: It's not manipulation, surely, to own a stock and then publicly announce that the stock is good. That's like half of financial television. It is also a big chunk of what corporate chief executive officers -- who all own their companies' stocks -- do. It's fine to short a stock and trash the company, or buy a stock and praise the company -- as long as, in each case, you're telling the truth.