I have a friend who once was roughed up by the so-called for-hire “private security” guards. This is a very common method that the imperialists and the fascists use to curtail, stifle and stop the constitutional guaranteed right of peacefully expressing one person's opinions.
It is something that is not limited to the for-profit rent-a-cop private security companies. The police in the United States will charge people with what they euphemistically call “disorderly conduct” using just about any excuse. All you have to do to find yourself physically abused by a cop and/or security guard is to say something that the rulers of the empire and the status-quo “protectors” dislike.
Freedom of speech is not one of the imperialists favored “rights.” Be prepared to suffer the consequences if you dare to speak out.
A case in point is what recently happened in Eqypt. Millions were peacefully protesting against a U.S. supported dictator. The western news media minimized the reports of the people who were being killed. After the dictator left Cairo, the true stories are beginning to emerge. 365 Egyptians were killed by the "security" forces.
At the end of the nineteenth century and the beggining of the twentieth century, hundreds were murdered and massacred by the thugs of corporate America, who battled those who were fighting for the rights of the working class.