How is this not market manipulation?

That is -not- what an activist investor is. An activist investor is someone that buys a large enough portion of a company in order to have a say in board operations, etc (even liquidation.) You can go on air and talk up your company, ever CEO, etc does that. That is expected. What he did was talk down positions he was going into. That is not activism.

> It's called activist investing.

I'd be really interested in learning more about the Olympic level mental gymnastics one has to go through to write this off as O.K. but then turn around and say that a bunch of random people on an open public forum saying to buy an over-shorted stock is market manipulation. They don't even have the purchasing power to make a difference here.

I remember, a few years back, that Musk made news because he shut down someone asking questions in a public earnings report. The press was giving him a lot of flack about it. Then I kept reading, and found out the person who was trying to ask those questions represented a firm(s) that had large short positions on the stock, and was trying to cause the stock to dip. Musk knew what was going on, and headed it off. Seemed like he made a good call, but then the press made THAT the story instead.