Opinion doesn't immunize against charge of libel in every case. In 1990 landmark decision, Milkovich v. Lorain Journal Co., 497 U.S. 1, the US Supreme Court rejected the argument that a separate opinion privilege existed against libel. In Kahn v. Bower (1991), California Supreme Court ruled that "no categorical exception for opinion exists independently under California law."

I think SK could build strong cases for defamation, character assassination and tortious interference.