The reason I doubted is because Google are using the "MPAA is targeting us" attack (subjective at best) instead of taking them to the cleaners with stock market manipulation (written law with precedent). This means that I must be missing something and possibly there is a subtle reason why this isn't stock market manipulation.
At least the article makes it sound like the stock manipulation is ancillary to Google's offense.
The one thing I can think of is that the manipulation seems not to be focused on gaining money directly by the stock market manipulation. That should still be illegal, but it makes the case a bit less clear cut.
Secondly, that seems to be a plan and not something that was actually done. Still illegal, but nothing where they could say "they harmed us, they have to pay us".
The other aspect might be that a separate legal win is not what Google is after with that specific document. It is already part of a court proceeding and shall help Google counter the subpoena and further actions against Google by Mississippi Attorney General Jim Hood, if I get the context right. To destroy those actions (and that man's career) would be a huge win for Google, going after specific individuals for stock price manipulation not. If I understand that right, that is something the state would have to do on its own anyway, in a normal criminal investigation, which would have to start now automatically.
I think part of the reason they're not pushing the stock price manipulation is that it would be very difficult to overcome a prosecutor's absolute immunity.
At least the article makes it sound like the stock manipulation is ancillary to Google's offense.