> Speech itself isn't protected if it is directed to incite or produce imminent lawless action. See Brandenburg v. Ohio
Correct, but for that argument to hold within the context of this case (EDIT: warrant) we would need the government to show that most people who visited this site did so with the intent to incite imminent lawless action. (Note, too, that Brandenburg v. Ohio specifically struck down a law banning the mere advocacy of violence.)
Disclaimer: I am not a lawyer. This is not legal advice.