Question

What is censorship?

It's the forcible prevention of the transmission of information. In the context of an adversarial situation, such as the invasion of a Free Nation by a Socialist State, the act of censorship is morally mandatory.  Such an invader has no more right to information about the defending forces than a biker gang has to the location of your wife or daughters.  In the context of a civil society, valid information concerning those holding or seeking public office and their goals and beliefs, is necessary in order for members of the electorate to make a valid decision when they exercise their authority.  To vote correctly, the voter needs to know the truth about office seekers and their beliefs and personal conduct.   Those who must suppress the transmission of valid information, such as corrupt office holders who are acting through their lieutenants, or through the local campus communist goon squad, are harmful to the individual citizens and the political community as a whole.  Those who attempt to practice censorship in a civil society are enemies of that society and must be identified and dealt with as such.