Yeah this was recently in the news in Massachusetts. It appears he persuaded a Mass. Senator to ask for investigations, in order to hurt the stock price and support Ackerman's short gamble:

> In Washington, Mr. Ackman’s efforts bore fruit on Jan. 23, when Mr. Markey’s office, which Mr. Ackman had lobbied himself and which had been provided with detailed information about Herbalife by Mr. Ackman’s team, sent letters to the S.E.C. and F.T.C., calling for investigations of the company. A little more than a half-hour after the stock began trading that day its value fell by 14 percent.

You could say that Ackerman sincerely believes the company is bad and is pursuing this for the greater good. The $1 billion is just putting his money where his mouth is. And his mouth just happens to be near a Senator's ear....