Instead, the complaint focuses on federal securities law, arguing that Facebook’s failure to tell shareholders about the extent of illegal activity on its platform is a violation of its fiduciary duty. If Facebook alienates advertisers and has to shoulder the true cost of scrubbing criminals from its social networks, it could affect investors in the company, the complaint argues.
FB has a long history of picking and choosing what it "thinks" is "good and bad" on its platform, but that seems to be a rather poor scale.