Hedge funds do that all
The time
Give us five examples of hedge funds doing this in the last year, then.
SPOILER: you can't, because it isn't true. It's an incredibly popular myth, but it is just a myth.
You've got one case, from three years ago, that was successfully prosecuted. So you're saying i'm right?
Here's another, claiming it's common: https://www.youtube.com/watch?v=gMShFx5rThI
Market manipulation is a crime under Section 9(a)(2) of the Securities Exchange Act of 1934. There is a big difference between buying or selling because you think a stock is over or under valued, and trying to manipulate a stock price to extract money from people not in on the manipulation.